@article {1371,
	title = {Seasonal activity and species composition of dung beetles (Coleoptera : Scarabaeidae and Geotrupidae) inhabiting cattle pastures in North Carolina},
	journal = {Annals Of The Entomological Society Of America},
	volume = {98},
	number = {3},
	year = {2005},
	note = {digital copy disease ecology, parasite transmission, scarbaeinae, ecological function},
	month = {May},
	pages = {309-321},
	abstract = {Species composition and seasonal distribution of dung beetles were studied on dairy and beef cattle pastures in North Carolina. Study sites included a dairy located in the piedmont region (North Carolina Department of Agriculture Piedmont Research Station, Salisbury, NC) and a combined dairy/beef facility in the coastal plain (North Carolina Department of Agriculture Center for Environmental Farming Systems, Goldsboro, NC). Dung beetles were trapped in cattle pastures from March 2002 through September 2003 by using dung-baited pitfall traps. Trapping yielded 4,111 beetles representing 14 species from the piedmont dairy, including Aphodius prodromus Brahm, a new record for North Carolina. Totals of 57,026 beetles representing 28 species and 28,857 beetles representing 26 species were trapped from the dairy unit and beef unit in the coastal plain site, respectively. Onthophagus gazella (F.), a second new record for North Carolina, was collected from the coastal plain. Beetles common to all collection sites include Aphodius erraticus (L.), Aphodius fimetarius (L.), Aphodius granarius (L.), Aphodius pseudolividus Balthasar, Onthophagus tattrus Scbreber, Onthophagus hecate hecate Panzer, and Onthophagus pennsylvanicus Harold. The introduced beetle O. taurus dominated the dung beetle population, accounting for \&GT; 50\% of the total beetles caught at either site. Beetle activity was greatest from March until November, with activity declining during the winter. Nine exotic species in the genera Onthophagus and Aphodius represented nearly 95\% of the beetles trapped.},
	keywords = {African buffalo fly, aphodius, bovine dung, canada, cattle, coastal-plain, diptera, dung beetle, flies, growth, habitat, muscidae, north america, north carolina dung beetle, Onthophagus, onthophagus-taurus, piedmont, SURVIVAL},
	url = {<Go to ISI>://000228963400009 },
	author = {Bertone, Matt and Green, Jim and Washburn, Steve and Poore, Matt and Sorenson, Clyde and Watson, D. Wes}
}
@article {1515,
	title = {Onthophagus yucatanus, a new species of the Clypeatus group from Mexico and Guatemala (Coleoptera: Scarabaeidae)},
	journal = {Florida Entomologist},
	volume = {89},
	number = {1},
	year = {2006},
	pages = {6-9},
	abstract = {A new Mexican and Guatemalan species, Onthophagus yucatanus , belonging to the Clypeatus group is described and illustrated. The distinctive characters of this species, its geographical distribution, and habits are described. },
	keywords = {Guatemala, Mexico, new species, Onthophagus, Scarabaeidae},
	author = {Delgado, Leonardo and Peraza, Lizandro N. and DeLoya, Cuauhtemoc}
}
@article {1561,
	title = {Alternative reproductive tactics and male-dimorphism in the horne beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae)},
	journal = {Behavioral Ecology and Sociobiology},
	volume = {41},
	year = {1997},
	month = {Aug},
	pages = {335-341},
	keywords = {alternative reproductive behavior, horned beetles, male competition, male dimorphism, Onthophagus},
	author = {Emlen, Douglas J.}
}
@article {1567,
	title = {Diversity in the weapons of sexual selection: horn evolution in the beetle genus Onthophagus (Coleoptera: Scarabaeidae)},
	journal = {Evolution},
	volume = {59},
	number = {5},
	year = {2005},
	month = {Jan},
	pages = {1060-1084},
	abstract = {Both ornaments and weapons of sexual selection frequently exhibit prolific interspecific diversity of form. Yet, most studies of this diversity have focused on ornaments involved with female mate choice, rather than on the weapons of male competition. With few exceptions, the mechanisms of divergence in weapon morphology remain largely unexplored. Here, we characterize the evolutionary radiation of one type of weapon: beetle horns. We use partial sequences from four nuclear and three mitochondrial genes to develop a phylogenetic hypothesis for a worldwide sample of 48 species from the dung beetle genus Onthophagus (Coleoptera: Scarabaeidae). We then use these data to test for multiple evolutionary origins of horns and to characterize the evolutionary radiation of horns. Although our limited sampling of one of the world{\textquoteright}s most species-rich genera almost certainly underestimates the number of evolutionary events, our phylogeny reveals prolific evolutionary lability of these exaggerated sexually selected weapons (more than 25 separate gains and losses of five different horn types). We discuss these results in the context of the natural history of these beetles and explore ways that sexual selection and ecology may have interacted to generate this extraordinary diversity of weapon morphology. },
	keywords = {Adaptive radiation, beetle horns, character divergence, male competition, Onthophagus, phylogeny, sexual selection, weapons.},
	author = {Emlen, Douglas J. and Marangelo, Jennifer and Ball, Bernard and Cunningham, Clifford}
}
@article {1791,
	title = {Genital morphology and fertilization success in the dung beetle Onthophagus taurus: an example of sexually selected male genitalia},
	journal = {Proceedings of the Royal society of London B},
	volume = {270},
	year = {2003},
	pages = {447-455},
	abstract = {In animals with internal fertilization and promiscuous mating, male genitalia show rapid and divergent evolution. Three hypotheses have been suggested to explain the evolutionary processes responsible for genital evolution: the lock-and-key hypothesis, the pleiotropy hypothesis and the sexual-selection hypoth- esis. Here, we determine whether variation in male genital morphology influences fertilization success in the dung beetle Onthophagus taurus, as predicted by the sexual-selection hypothesis. Variation in four out of five genital sclerites of the endophallus influenced a male{\textquoteright}s fertilization success, supporting the general hypothesis that male genitalia can evolve under sexual selection. Furthermore, different genital sclerites were found to enhance first versus second male paternity, indicating that different sclerites serve offensive and defensive roles. Genital-trait variability was comparable to that in other species but was less variable than a non-genital sexually selected trait (head horns). We suggest that directional selection for genital elaboration may be countered by natural selection, which should favour genitalia of a size and shape necessary for efficient coupling and sperm transfer. },
	keywords = {male genitalia, Onthophagus, paternity, sexual selection, Sperm competition},
	author = {House, Clarissa M. and Simmons, Leigh W.}
}
@article {1858,
	title = {Optimal investment in sons and daughters when parents do not know the sex of their offspring},
	journal = {Behavioral Ecology and Sociobiology},
	volume = {62},
	year = {2008},
	pages = {607-615},
	abstract = {Optimal parental i nvestment usually differs depending on the sex of the offspring. However, parents in most organisms cannot discriminate the sex of their young until those young are energetically independent. In a species with physical male{\textendash}male competition, males are often larger and usually develop sexual ornaments, so male offspring are often more costly to produce. However, Onthophagus dung beetles (Coleoptera; Scarabaeidae) are highly dimorphic in secondary sexual characters, but sexually monomorphic in body size, despite strong male{\textendash}male competition for mates. We demonstrate that because parents provide all resources required by their offspring before adulthood, O. atripennis exhibits no sexual size dimorphism irrespective of sexual selection pressure favoring sexual dimorphism. By con- structing a graphic model with three fitness curves (for sons, daughters, and expected fitness return for parents), we demonstrate that natural selection favors parents that provide both sons and daughters with the optimal amount of investment for sons, which is far greater than that for daughters. This is because the cost of producing small sons, that are unable to compete for mates, is far greater than the cost of producing daughters that are larger than necessary. This theoretical prediction can explain sexual dimorphism without sexual size dimorphism, widely observed in species with crucial parental care such as dung beetles and leaf- rolling beetles, and may provide an insight into the enigmatic relationship between sexual size dimorphism and sexual dimorphism.},
	keywords = {dung beetle, Onthophagus, Optimal investment, Sexual dimorphism, Sexual size dimorphism},
	author = {Kishi, Shigeki and Nishida, Takayoshi}
}
@article {1870,
	title = {Sexual selection and condition dependence of courtship display in three species of horned dung beetles},
	journal = {Behavioral Ecology},
	volume = {13},
	number = {6},
	year = {2002},
	note = {Times Cited: 0Cited Reference Count: 62Cited References:      ANDERSSON M, 1986, EVOLUTION, V40, P804     ANDERSSON M, 1994, SEXUAL SELECTION     ANDERSSON M, 1996, TRENDS ECOL EVOL, V11, P53     ARNOLD SJ, 1984, EVOLUTION, V38, P709     BERGLUND A, 1996, BIOL J LINN SOC, V58, P385     BORGIA G, 1979, SEXUAL SELECTION REP, P19     BRODIE ED, 1995, TRENDS ECOL EVOL, V10, P313     BROWN L, 1985, ANN ENTOMOL SOC AM, V78, P423     CANDOLIN U, 1999, ANIM BEHAV 6, V58, P1261     CANDOLIN U, 2000, BEHAV ECOL SOCIOBIOL, V49, P57     CANDOLIN U, 1999, P ROY SOC LOND B BIO, V266, P785     CHARLESWORTH B, 1987, SEXUAL SELECTION TES, P21     COOK D, 1988, AUST J ZOOL, V36, P521     COOK D, 1987, AUST J ZOOL, V35, P123     COOK DF, 1990, ANIM BEHAV, V40, P428     DARWIN CR, 1871, DESCENT MAN SELECTIO     DAVID P, 2000, NATURE, V406, P186     DAVID P, 1998, P ROY SOC LOND B BIO, V265, P2211     EBERHARD WG, 1982, AM NAT, V119, P420     EBERHARD WG, 1991, EVOLUTION, V45, P18     EBERHARD WG, 1987, J KANSAS ENTOMOL SOC, V60, P504     EBERHARD WG, 1979, SEXUAL SELECTION REP, P231     EMLEN DJ, 1997, BEHAV ECOL SOCIOBIOL, V41, P335     EMLEN DJ, 1994, P ROY SOC LOND B BIO, V256, P131     EMLEN ST, 1977, SCIENCE, V197, P215     ENDLER JA, 1986, NATURAL SELECTION WI     FALCONER DS, 1989, INTRO QUANTITATIVE G     FRISCHKNECHT M, 1993, EVOL ECOL, V7, P439     GRAFEN A, 1990, J THEOR BIOL, V144, P517     GRIFFITH SC, 1999, NATURE, V400, P358     HARDY ICW, 1998, ANIM BEHAV 3, V56, P787     HUNT J, 1998, BEHAV ECOL SOCIOBIOL, V42, P447     HUNT J, 1997, BEHAV ECOL SOCIOBIOL, V41, P109     HUNT J, 1999, ECOL ENTOMOL, V24, P174     HUNT J, 2000, EVOLUTION, V54, P936     HUNT J, 2002, J EVOLUTION BIOL, V15, P57     JANZEN FJ, 1998, EVOLUTION, V52, P1564     JOHNSTONE RA, 1995, BIOL REV, V70, P1     KEYSER AJ, 1999, P ROY SOC LOND B BIO, V266, P771     KIRKPATRICK M, 1982, EVOLUTION, V36, P1     KIRKPATRICK M, 1991, NATURE, V350, P33     KOKKO H, 1998, EVOL ECOL, V12, P739     KOTIAHO JS, 2001, BEHAV ECOL, V12, P553     KOTIAHO JS, 2000, BEHAV ECOL SOCIOBIOL, V48, P188     KOTIAHO JS, 2001, BIOL REV, V76, P365     KOTIAHO JS, 2001, NATURE, V410, P684     KOTIAHO JS, 1999, OIKOS, V87, P399     LANDE R, 1983, EVOLUTION, V37, P1210     MAPPES J, 1996, P ROY SOC LOND B BIO, V263, P785     MILINSKI M, 1990, NATURE, V344, P330     MOCZEK AP, 2000, ANIM BEHAV 2, V59, P459     OTRONEN M, 1988, ANIM BEHAV, V36, P741     PALMER TJ, 1978, NATURE, V274, P583     RASMUSSEN JL, 1994, J INSECT BEHAV, V7, P67     ROFF D, 1997, EVOLUTIONARY QUANTIT     ROWE L, 1996, P ROY SOC LOND B BIO, V263, P1415     SIMMONS LW, 1999, P ROY SOC LOND B BIO, V266, P145     SIVAJOTHY MT, 1987, J ETHOL, V5, P165     TAYLOR PD, 1982, THEOR POPUL BIOL, V22, P392     TOMKINS JL, 1998, ANIM BEHAV 2, V56, P347     WILKINSON GS, 1999, P ROY SOC LOND B BIO, V266, P1685     ZAHAVI A, 1977, J THEOR BIOL, V67, P603EnglishArticle619YBBEHAV ECOL},
	month = {Nov-Dec},
	pages = {791-799},
	abstract = {Sexual selection has traditionally been divided into competition over mates and mate choice. Currently, models of sexual selection predict that sexual traits are expressed in proportion to the condition of their bearer. In horned beetles, male contest competition is well established, but studies on female preferences are scarce. Here I present data on male mating success and condition dependence of courtship rate in three species of horn-dimorphic thing beetles, Onthaphagus taurus, Onthophagus binodis, and Onthophagus australis. I found that in the absence of male contest competition, mating success of O. taurus and O. australis was unrelated to their horn length and body size, whereas in O. binodis horn size had a negative effect but body size had a positive effect on male mating success. Overall, in O. binodis major morph males had greater mating success than minor morph males. In all three species male mating success was affected by courtship rate, and the Courtship rate was condition dependent such that when males were manipulated to be in poor condition they had lower courtship rates than males that were manipulated to be in good condition. My findings provide new insight into the mating systems of horned dung beetles and support an important assumption in indicator models of sexual selection.},
	keywords = {alternative reproductive, condition dependence, FEMALE CHOICE, gradient, horn dimorphism, horned dung beetles, lek, logistic regression, mating success, Onthophagus, onthophagus-acuminatus coleoptera, SELECTION, sexual selection, stalk-eyed flies, tactics},
	url = {<Go to ISI>://000179504300011},
	author = {Kotiaho, J. S.}
}
@article {1927,
	title = {Relaciones entre escarabajos (Coleoptera: Scarabaeidae) y nidos de tuza (Rodentia: Geomydae): implicaciones biologicas y biogeograficas},
	journal = {Acta Zoologica Mexicana (nueva serie)},
	volume = {62},
	year = {1994},
	pages = {1-9},
	keywords = {{\textquoteright}, association with rodents, nests, Onthophagus, Scarabaeinae},
	author = {Lobo, Jorge M. and Halffter, Gonzalo}
}
@article {1636,
	title = {Experimental investigations of colonisation by north temperate dung beetles of different types of domestic herbivore dung},
	journal = {Applied Soil Ecology},
	volume = {20},
	number = {1},
	year = {2002},
	note = {Times Cited: 1Cited Reference Count: 33Cited References:      ASCHENBORN HH, 1989, ENTOMOL EXP APPL, V53, P73     BARBERO E, 1999, J INSECT CONSERVATIO, V3, P75     BISTROM O, 1991, ENTOMOL FENNICA, V2, P53     BREYMEYER A, 1975, B ACAD POLONAISE SB, V23, P173     DADOUR IR, 1996, ENVIRON ENTOMOL, V25, P1026     DANIEL WW, 1978, APPL NONPARAMETRIC S     EDWARDS PB, 1991, FUNCT ECOL, V5, P617     FINN JA, 1998, APPL SOIL ECOL, V10, P27     FINN JA, 2000, ECOGRAPHY, V23, P301     FINN JA, 1999, ECOL ENTOMOL, V24, P24     FINN JA, 1998, THESIS NATL U IRELAN, P199     GITTINGS T, 1998, ECOGRAPHY, V21, P581     GITTINGS T, 1997, ECOGRAPHY, V20, P55     GITTINGS T, 1994, PEDOBIOLOGIA, V38, P455     GITTINGS T, 1994, THESIS NATL U IRELAN, P323     GREENHAM PM, 1972, J ANIM ECOL, V41, P153     HANSKI I, 1991, DUNG BEETLE ECOLOGY, P75     HIMMELSBACH W, 1993, THESIS FREIBURG     HIRSCHBERGER P, 1994, PEDOBIOLOGIA, V38, P375     HOLTER P, 1983, EARTHWORM ECOLOGY, P49     HOLTER P, 1979, ECOL ENTOMOL, V4, P317     HOLTER P, 1982, OIKOS, V39, P213     HOLTER P, 1979, OIKOS, V32, P393     KIELY J, 1984, SOIL SURVEY B FORAS, V38     LUMARET JP, 1993, J APPL ECOL, V30, P428     MACQUEEN A, 1986, J AUST ENTOMOL SOC, V25, P23     OLECHOWICZ E, 1974, ECOL POL, V22, P589     PALMER WA, 1983, PROT ECOL, V5, P153     RAINIO M, 1966, ANN ZOOL FENN, V3, P88     RASSI P, 1991, 30 MIN ENV, P328     RIDSDILLSMITH TJ, 1986, B ENTOMOL RES, V76, P63     SOWIG P, 1994, ZOOL JB SYST, V121, P171     TYNDALEBISCOE M, 1981, B ENTOMOL RES, V71, P137EnglishArticle578NGAPPL SOIL ECOL},
	month = {Apr},
	pages = {1-13},
	abstract = {Field experiments investigated the colonisation by a north temperate dung beetle community (Aphodius, Geotrupes and Sphaeridium species) of artificial, standardised (11) dung pats from native herbivore species (cow, horse and sheep). An additional experiment compared the colonisation by dung beetles of five different types of cow dung. These experiments did not examine naturally occurring dung pats, but used experimental dung pats to examine the ability of north temperate dung beetles to discriminate among different dung types. A small number of laboratory experiments investigated pat residence times (PRT) and larval production across different dung types. There were significant differences in the biomass and abundance of dung beetle colonisation across different dung types. Sheep dung tended to have highest abundances of beetles, but there was evidence of species-specific differences in dung beetle colonisation of the different kinds of dung. In two out of three comparisons, laboratory experiments provided evidence that adult PRT were significantly different among different kinds of dung. In each of three laboratory experiments, larval production was significantly higher in sheep than cow dung pats of the same size. The relevance of these findings to the interpretation of what constitutes a dung type preference is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.},
	keywords = {abundance, aphodius, assemblage, cattle dung, COLEOPTERA, colonisation, disappearance, dung beetle, Onthophagus, resource, resource utilization, Scarabaeidae, Scarabaeoidea, seasonal-changes, utilisation},
	url = {<Go to ISI>://000177123900001},
	author = {Finn, J. A. and Giller, P. S.}
}
@article {2026,
	title = {Horn polyphenism in the beetle Onthophagus taurus: larval diet quality and plasticity in parental investment determine adult body size and male horn morphology},
	journal = {Behavioral Ecology},
	volume = {9},
	number = {6},
	year = {1998},
	pages = {636-641},
	keywords = {alternative phenotypes, facultative parental investment, Onthophagus, phenotypic plasticity, Polyphenism},
	author = {Moczek, Armin P.}
}
@article {2027,
	title = {Facultative paternal investment in the polyphenic beetle Onthophagus taurus; the role of male morphology and social context},
	journal = {Behavioral Ecology},
	volume = {10},
	number = {6},
	year = {1999},
	pages = {641-647},
	keywords = {beetles, facultative parental investment, honest indicators, Onthophagus, phenotypic plasticity, Polyphenism, sexual selection},
	author = {Moczek, Armin P.}
}
@article {2028,
	title = {Allometric plasticity in a polyphenic beetle},
	journal = {Ecological Entomology},
	volume = {27},
	number = {1},
	year = {2002},
	note = {Times Cited: 0Cited Reference Count: 69Cited References:      BAHRENS D, 1960, MORPHOLOGISCHES JB, V101, P279     BALTHASAR V, 1963, MONOGRAPHIE SCARABAC, V2     BOCQUET C, 1953, ARCH ZOOLOGIE EXPT G, V90, P187     BROWN L, 1986, AM NAT, V127, P565     BROWN L, 1983, ANN ENTOMOLOGICAL SO, V76, P253     CLARK JT, 1977, SYST ENTOMOL, V2, P9     COCK AG, 1966, Q REV BIOL, V41, P131     DEWILDE H, 1982, ADV INSECT PHYSL, V19, P167     EBERHARD WG, 1982, AM NAT, V119, P420     EMLEN DJ, 2000, ANNU REV ENTOMOL, V45, P661     EMLEN DJ, 1997, BEHAV ECOL SOCIOBIOL, V41, P335     EMLEN DJ, 1996, EVOLUTION, V50, P1219     EMLEN DJ, 2001, J INSECT PHYSIOL, V47, P1045     EMLEN DJ, 1999, J INSECT PHYSIOL, V45, P45     EMLEN DJ, 1997, P ROY SOC LOND B BIO, V264, P567     EMLEN DJ, 1994, P ROY SOC LOND B BIO, V256, P131     FEENER DH, 1988, FUNCTIONAL ECOLOGY, V2, P509     FINCHER GT, 1975, COLEOPT B, V29, P349     GOIDANICH A, 1964, ANN FAC SC AGR U TOR, V2, P213     GOIDANICH A, 1962, ATTI ACCAD SCI TORIN, V96, P575     GOLDSMITH SK, 1985, J KANSAS ENTOMOL SOC, V58, P534     GOULD SJ, 1966, BIOL REV CAMBRIDGE P, V41, P587     GOULD SJ, 1974, EVOLUTION, V28, P191     GREEN AJ, 1992, ANIM BEHAV, V43, P170     GROSS MR, 1996, TRENDS ECOL EVOL, V11, P92     HALFFTER G, 1982, NESTING BEHAV DUNG B     ITO F, 1994, ANN ENTOMOL SOC AM, V87, P337     KAWANO K, 1997, ANN ENTOMOL SOC AM, V90, P453     KAWANO K, 1995, ANN ENTOMOL SOC AM, V88, P92     KAWANO K, 1995, ANN ENTOMOL SOC AM, V88, P641     KERMACK KA, 1954, PHILOS T ROY SOC B, V237, P375     KLINGENBERG CP, 1996, ADV MORPHOMETRICS, P23     KLINGENBERG CP, 1992, AM NAT, V140, P601     KNELL RJ, 1999, ECOL ENTOMOL, V24, P323     KURTEN B, 1964, ACTA ZOOL FENN, V108, P1     KURTEN B, 1954, ACTA ZOOL FENN, V85, P1     LOZAN JL, 1992, ANGEW STAT NATURWISS     MILTON K, 1982, FORAGING STRATEGY HO     MILTON K, 1991, J ECOL, V79, P1     MILTON K, 1980, PHYSIOL ZOOL, V53, P402     MITRA KC, 1958, J PALEONTOL, V32, P992     MOCZEK AP, 2000, ANIM BEHAV 2, V59, P459     MOCZEK AP, 1999, BEHAV ECOL, V10, P641     MOCZEK AP, 1998, BEHAV ECOL, V9, P636     MOCZEK AP, 1999, J EVOLUTION BIOL, V12, P27     MOCZEK AP, 1996, THESIS J MAXIMILIANS     NAGY KA, 1979, ECOLOGY, V60, P475     PALESTRINI C, 2000, CAN J ZOOL, V78, P1199     PASSERA L, 1985, CASTE DIFFERENTIATIO, P331     PASSERA L, 1974, INSECT SOC, V21, P71     PETRIE M, 1992, ANIM BEHAV, V43, P173     PETRIE M, 1988, ANIM BEHAV, V36, P1174     ROFF DA, 1996, Q REV BIOL, V71, P3     SACHS L, 1992, ANGEW STAT     SCHLICHTING CD, 1998, REACTION NORM PERSPE     SCHMALHAUSEN II, 1949, FACTORS EVOLUTION     SHAFIEI M, 2001, PHYSIOL ENTOMOL, V26, P173     SHAPIRO A, 1976, EVOL BIOL, V9, P259     SIMMONS LW, 1996, EVOL ECOL, V10, P97     SIMMONS LW, 1999, P ROY SOC LOND B BIO, V266, P145     SOKAL RR, 1995, BIOMETRY     THOMPSON DW, 1942, ON GROWTH FORM     TOMKINS JL, 1999, BEHAV ECOL SOCIOBIOL, V47, P1     TYNDALEBISCOE M, 1990, COMMON DUNG BEETLES     WENZEL JW, 1992, INSECT SOC, V39, P31     WHEELER DE, 1991, AM NAT, V138, P1218     WHEELER DE, 1986, AM NAT, V128, P13     WHEELER DE, 1984, J INSECT PHYSIOL, V30, P127     WHEELER DE, 1983, J INSECT PHYSIOL, V29, P847EnglishArticle530MJECOL ENTOMOL},
	month = {Feb},
	pages = {58-67},
	abstract = {1. Environmental conditions. such as variation in nutrition. commonly contribute to morphological variation among individuals by affecting body size and the expression of certain morphological traits however the scaling relationship between a morphological trait and body size over a range of body sizes is generally assumed not to change in response to environmental fluctuation (allometric plasticity), but instead to be constant and diagnostic for a particular trait and species or Population. The work reported here examined diet- induced allometric plasticity in the polyphenic beetle Onthophagus taurus Schreber (1759) (Coleoptera: Scarabaeidae). 2. Male O. taurus vary in body size depending on larval nutrition, Only males above a critical body size threshold express fully developed horns: males smaller than this threshold develop only rudirrientary horns or no horns at all. 3. Field populations that naturally utilise two different resources for feeding larvae (horse dung vs. cow manure) exhibited significant differences in the average scaling relationship between body size and male horn length over the same range of body sizes. Males collected from cow manure populations expressed consistently longer horns for a given body size than males collected from horse dung Populations. 4. Males reared in the laboratory on horse dung or cow manure also exhibited significant differences in the average scaling relationship between body size and horn length. Differences between laboratory populations reared on horse dung or cow manure were of the same kind and magnitude as differences between field populations that utilise these different resources naturally. 5. These findings suggest that between- population differences in scaling relationships between horn length and body size can be the product of differences in the quality of resources available to developing larvae. Results are discussed in the context of onthophagine mating systems and recent insights in the developmental and endocrine control of horn polyphenisms.},
	keywords = {adaptive phenotypic plasticity, allometric plasticity, alternative reproductive, alternative tactics, developmental threshold, horn polyphenism, male, Onthophagus, onthophagus-acuminatus coleoptera, status-dependent selection, tactics, threshold evolution},
	url = {<Go to ISI>://000174361200008},
	author = {Moczek, A. P.}
}
@article {2029,
	title = {The behavioral ecology of threshold evolution in a polyphenic beetle},
	journal = {Behavioral Ecology},
	volume = {14},
	number = {6},
	year = {2003},
	pages = {841-854},
	abstract = {Facultative expression of alternative male morphologies is thought to allow individual males to select the phenotype with the highest fitness gain given their competitive status relative to other males with which they compete for females. Choice of, or switching between, morphs commonly relies on developmental threshold responses. Evolutionary changes in developmental threshold responses are thought to provide an important avenue for phenotypic diversification and the evolution of morphological and behavioral novelties. However, the extent to which alternative male phenotypes and their underlying threshold responses actually evolve in natural populations is unclear. Likewise, the ecological factors that shape the evolution of threshold responses in natural populations are unexplored for most organisms, as are the consequences of such modifications for patterns of morphological diversity. I examined the ecological basis of rapid threshold evolution in exotic populations of the horn-polyphenic dung beetle Onthophagus taurus. Male O. taurus vary continuously in body size as a function of larval feeding conditions. Only males that exceed a critical threshold body size develop a pair of long horns on their heads, whereas males below this threshold remain hornless. Populations in two exotic ranges of this species, the eastern United States and western Australia, have diverged in the mean threshold body size, which has resulted in the evolution of highly divergent and novel horn length{\textendash}body size allometries in these populations. Populations in a third and previously unstudied exotic range of O. taurus in eastern Australia exhibit threshold body sizes roughly intermediate between the eastern U.S. and western Australian populations. I tested three hypothesis to explain how differences in ecological and demographic factors can drive allometric divergences between populations, using data derived from comparative, standardized sampling of a large number of populations in each exotic range. Results suggest that differences in the intensity of both intra- and interspecific competition have contributed to the evolution of divergent thresholds in these populations. My results do not support the hypothesis that shifts in threshold body sizes to larger body sizes are a consequence of increases in the mean body size of competing males. I discuss my results in the context of Onthophagus mating systems and the evolutionary implications of threshold evolution.},
	keywords = {adaptive phenotypic plasticity, developmental threshold, exotic species, horned beetles, male, Onthophagus, Polyphenism, resource competition, sex ratio evolution, status-dependent selection, threshold evolution, {\textendash}male competition},
	author = {Moczek, Armin P.}
}
@article {2030,
	title = {Pupal remodeling and the development  and evolution of sexual dimorphism in horned beetles},
	journal = {The American Naturalist},
	volume = {168},
	number = {6},
	year = {2006},
	month = {dec},
	pages = {711-729},
	keywords = {allometry, evolvability, lability, Onthophagus, programmed cell death, pupal remodeling},
	author = {Moczek, Armin P.}
}
@article {2032,
	title = {Linear and threshold-dependent expression of secondary sexual traits in the same individual: insights from a horned beetle (Coleoptera: Scarabaeidae)},
	journal = {Biological Journal of the Linnean Society},
	volume = {83},
	year = {2004},
	pages = {473-480},
	abstract = {Elaborate horns or horn-like structures in male scarab beetles commonly scale with body size either (a) in a linear fashion with horn size increasing relatively faster than body size or (b) in a threshold-dependent, sigmoid fashion; that is, males smaller than a certain critical body size develop no or only rudimentary horns, whereas males larger than the threshold size express fully developed horns. The development of linear vs. sigmoid scaling relationships is thought to require fundamentally different regulatory mechanisms. Here we show that such disparate regulatory mechanisms may co-occur in the same individual. Large males of the south-east Asian Onthophagus  ( Proagoderus ) watanabei  (Ochi \& Kon) (Scarabaeidae, Onthophagini) develop a pair of long, curved head horns as well as a single thoracic horn. We show that unlike paired head horns in a large number of Onthophagus  species, in O. watanabei  the relationship between head horns and body size is best explained by a linear model. Large males develop dispropor- tionately longer horns than small males, but the difference in relative horn sizes across the range of body sizes is small compared to other Onthophagus  species. However, the scaling relationship between the thoracic horn and body size is best explained by a strongly sigmoid model. Only males above a certain body size threshold express a thoracic horn and males smaller than this threshold express no horn at all. We found a significant positive correlation between head and thoracic horn length residuals, contrary to what would be expected if a resource allocation tradeoff during larval development would influence the length of both horn types. Our results suggest that the scaling rela- tionship between body size and horn length, and the developmental regulation underlying these scaling relation- ships, may be quite different for different horns, even though these horns may develop in the same individual. We discuss our results in the context of the developmental biology of secondary sexual traits in beetles.},
	keywords = {allometry, developmental constraint, developmental tradeoff, Onthophagus, scaling},
	author = {Moczek, Armin P. and Bruhl, Carsten and Krell, Frank-Thorsten}
}
@article {2035,
	title = {Threshold evolution in exotic populations of a polyphenic beetle},
	journal = {Evolutionary Ecology Research},
	volume = {4},
	year = {2002},
	pages = {587-601},
	abstract = {Polyphenic development is thought to play an important role in the evolution of phenotypic diversity and morphological novelties, yet the evolution of polyphenisms has rarely been docu- mented in natural populations. Here we compare the morphologies of male dung beetles (Onthophagus ttaurus; Coleoptera: Scarabaeidae) from populations introduced to Australia and the eastern United States. Males in this species express two alternative morphologies in response to larval feeding conditions. Males encountering favourable conditions grow larger than a threshold body size and develop a pair of horns on their heads, whereas males that encounter poor conditions do not reach this threshold size and remain hornless. Australian and US populations did not differ in overall body size ranges, but exhibited significant differences in the location of the critical body size threshold that separates alternative male morphs. Australian males remained hornless at much larger body sizes than males in US populations, resulting in substantial and significant differences in the average body size{\textendash}horn length allometry between exotic populations, as well as significant differences in morph ratios. The phenotypic divergence observed between field populations was maintained in laboratory populations after two generations under identical environmental conditions, suggesting a genetic basis to allometric divergence in these populations. Divergence between exotic O. taurus populations was of a magnitude and kind typically observed between species. We use our results to examine potential causes of allometric divergence in onthophagine beetles, and discuss the evolutionary potential of threshold traits and polyphenic development in the origin of morphological and behavioural diversity.},
	keywords = {adaptive phenotypic plasticity, alternative tactics, developmental threshold, exotic species, horn polyphenism, Onthophagus, status-dependent selection, threshold evolution.},
	author = {Moczek, Armin P. and Hunt, John and Emlen, Douglas J. and Simmons, Leigh W.}
}
@article {2037,
	title = {Trade-offs during the development of primary and secondary sexual traits in a horned beetle},
	journal = {The American Naturalist},
	volume = {163},
	number = {2},
	year = {2004},
	pages = {184-191},
	abstract = { Resource allocation trade-offs during development affect the final sizes of adult structures and have the potential to constrain the types and magnitude of evolutionary change that developmental processes can accommodate. Such trade-offs can arise when two or more body parts compete for a limited pool of resources to sustain their growth and differentiation. Recent studies on several holo- metabolous insects suggest that resource allocation trade-offs may be most pronounced in tissues that grow physically close to each other. Here we examine the nature and magnitude of developmental trade-offs between two very distant body parts: head horns and geni- talia of males of the horned scarab beetle Onthophagus taurus. Both structures develop from imaginal disklike tissues that undergo ex- plosive growth during late larval development but differ in exactly when they initiate their growth. We experimentally ablated the pre- cursor cells that normally give rise to male genitalia at several time points during late larval development and examined the degree of horn development in these males compared to that of untreated and sham-operated control males. We found that experimental males developed disproportionately larger horns. Horn overexpression was weakest in response to early ablation and most pronounced in males whose genital disks were ablated just before larvae entered the pre- pupal stage. Our results suggest that even distant body parts may rely on a common resource pool to sustain their growth and that the relative timing of growth may play an important role in deter- mining whether, and how severely, growing organs will affect each other during development. We use our findings to discuss the phys- iological causes and evolutionary consequences of resource allocation trade-offs. },
	keywords = {beetle horns, developmental timing, genitalia, imaginal disk, Juvenile hormone, Onthophagus, resource allocation trade-off},
	author = {Moczek, Armin P. and Nijhout, H. Frederik}
}
@article {2096,
	title = {Body size and paternal invest ment in the genus Onthophagus (Coleoptera, Scarabaeoidea)},
	journal = {Journal of Zoology},
	volume = {255},
	year = {2001},
	note = {EnglishArticleNOV3J ZOOL},
	pages = {405-412},
	abstract = {During reproduction, dung beetles of the genus Onthophagus typically bury portions of dung removed from the dung pad. Even though females are capable of successfully constructing and provisioning nests when unaccompanied by males, extensive levels of co-operation between sexes have been reported. In some species, males show a clear dimorphism in body plan and only large horned males are known to assist females. In O. taurus this form of paternal investment is facultative and depends on social context (namely the presence of other males). We studied relationships between body size and paternal investment in five Onthophagus species (i.e. O. coenobita, O. fracticornis, O. illyricus, O. taurus and O. vacca). Two types of tests were established. In test A, a large and a small male were placed with a single, medium-size female, in test B, a large and a small female were placed with a single large male. In controls one male was placed with one female. Individuals were maintained for 10 days. Then the enclosures were opened to assess the position of each beetle. When two mates were found in close vicinity or in the same tunnel provisioning dung, a co-operative behaviour was assumed. In competitive tests, small males and small females never cooperated with their potential mates whilst large and medium-size individuals often co- operated with mates inside the same tunnels. No differences in frequencies of co-operation were found between large and medium-size females. Small females and small males scarcely co- operated with large or medium-size mates in controls. These results suggest that large individuals outcompete the small ones. They also suggest that paternal investment depends on body size of both mates. Large males of all species assist medium-size and large females, whereas small males do not. However, large males do not invest much parental effort on small females that, in fact, are poorly, assisted. We assume that large individuals of both sexes are reproductively superior to small ones. The propensity of both small females and small males to excavate was lower than that of larger individuals, accordingly, digging capacity could be a proximate factor explaining facultative paternal investment in these species.},
	keywords = {ACUMINATUS COLEOPTERA, ALTERNATIVE REPRODUCTIVE TACTICS, beetle, body size, BROOD CARE, co-operation, Dung beetles, investment, MALE HORN DIMORPHISM, MALE MORPHOLOGY, Onthophagus, paternal, reproduction, Scarabaeidae, TAURUS COLEOPTERA, VACCA COLEOPTERA},
	author = {Palestrini, C. and Rolando, A.}
}
@article {2098,
	title = {Rapid antagonistic coevolution between primary and secondary sexual characters in horned beetles},
	journal = {Evolution},
	volume = {62},
	number = {9},
	year = {2008},
	month = {sep},
	pages = {2423-2428},
	abstract = {Different structures may compete during development for a shared and limited pool of resources to sustain growth and differ- entiation. The resulting resource allocation trade-offs have the potential to alter both ontogenetic outcomes and evolutionary trajectories. However, little is known about the evolutionary causes and consequences of resource allocation trade-offs in natural populations. Here, we explore the significance of resource allocation trade-offs between primary and secondary sexual traits in shaping early morphological divergences between four recently separated populations of the horned beetle Onthophagus taurus as well as macroevolutionary divergence patterns across 10 Onthophagus species. We show that resource allocation trade-offs leave a strong signature in morphological divergence patterns both within and between species. Furthermore, our results suggest that genital divergence may, under certain circumstances, occur as a byproduct of evolutionary changes in secondary sexual traits. Given the importance of copulatory organ morphology for reproductive isolation our findings begin to raise the possibility that secondary sexual trait evolution may promote speciation as a byproduct. We discuss the implications of our results on the causes and consequences of resource allocation trade-offs in insects. },
	keywords = {Aedeagus, Horned beetle, Onthophagus, resource allocation trade-off, speciation},
	author = {Parzer, Harald F. and Moczek, Armin P.}
}
@article {2200,
	title = {Food availability controls the onset of metamorphosis in the dung beetle Onthophagus taurus (Coleoptera: Scarabaeidae)},
	journal = {Physiological Entomology},
	volume = {26},
	year = {2001},
	pages = {173-180},
	keywords = {developmental cues, dung beetle, larval development, Onthophagus, regulation of pupation, timing of metamorphosis},
	author = {Shafiei, Majid and Moczek, Armin P. and Nijhout, H. Frederik}
}
@book {2363,
	title = {An{\'a}lisis taxon{\'o}mico, ecol{\'o}gico y biogeogr{\'a}fico de un grupo americano de Onthophagus (Coleoptera, Scarabaeidae)},
	year = {1988},
	note = {have copy},
	publisher = {Torino : Museo regionale di scienze naturali},
	organization = {Torino : Museo regionale di scienze naturali},
	address = {Torino},
	keywords = {dung beetle, food resources mammals, Onthophagus, Scarabaeinae},
	author = {Zunino, M. and Halffter, Gonzalo}
}
