@article {1456,
	title = {Differences in courtship, mating and postcopulatory behavior between male morphs of the dung beetle Onthophagus binodis Thunberg (Coleoptera: Scarabaeidae)},
	journal = {Animal Behavior},
	volume = {40},
	number = {3},
	year = {1990},
	pages = {428-436},
	abstract = {Large, horned males of the dung beetle Onthophagus binodis assisted their mates in gathering larval provisions and guarded their mates{\textquoteright} burrows when vacated. The horned males{\textquoteright} assistance is expected to increase their mates{\textquoteright} reproductive success. In contrast, small, hornless males did not appear to help females during oviposition. Differences in courtship behaviour between the male morphs indicated that large, horned males may be assessing female size and employing precopulatory mate discrimination. Under laboratory conditions small, hornless males inseminated females on the first encounter more often than large, horned males and presumably exercise minimal mate discrimination. However, the mating frequencies of the male morphs may be different in the field as a result of either intrasexual selection or female choice. Features of mating in O. binodis were the male{\textquoteright}s (1) tactile stimulation of the female, and (2) upward jerks of the head and pronotum before, during and after copulation. This latter action would facilitate dissemination of pheromones from the exocrine glands on their forelegs. },
	author = {Cook, D. F.}
}
@article {1718,
	title = {Parental care and offspring survival in Copris incertus Say, a sub-social beetle},
	journal = {Animal Behavior},
	volume = {52},
	number = {1},
	year = {1996},
	pages = {133-139},
	abstract = {The effects of the lack of maternal care on offspring survival of the sub-social beetle Copris incertus Say (Coleoptera: Scarabaeidae: Scarabaeinae) were tested experimentally by excluding the female and determining the most vulnerable stage of development. Time budget studies were also conducted to determine the amount used by 10 females during the whole cycle from the making of the nest to the emergence of adults. A Kruskal{\textendash}Wallis test and the subsequent non-parametric multiple comparisons showed a significant difference in survival between nests cared for by the mother and nests where the mother was excluded. Key-factor analysis showed that the absence of parental care affected offspring survival in the transition from the pupal to adult stage. Time budget studies indicated that, whether active or inactive, females were in direct association with the brood balls. Balls that received no care (in experimental exclusions or where the female abandoned the nest) were invaded by the fungi Metarrhizium anisoplae and Cephalosporium sp., which covered the surface and the inner part of the ball, considerably affecting pupal survivorship. Results show that sub-social care increases the probability of juveniles reaching adulthood. },
	author = {Halffter, Gonzalo and Huerta, Carmen and Lopez-Portillo, Jorge}
}
@article {2034,
	title = {Male horn dimorphism in the scarab beetle, Onthophagus taurus: do alternative reproductive tactics favour alternative phenotypes},
	journal = {Animal Behavior},
	volume = {59},
	year = {2000},
	pages = {459-466},
	abstract = {In a variety of organisms morphological variation is discrete rather than continuous. Discrete variation within a sex has attracted particular interest as it is thought to reflect the existence of alternative adaptations to a heterogeneous selection environment. The beetle Onthophagus taurus shows a dimor- phism for male horns: males that exceed a critical body size develop a pair of long, curved horns on their heads, while smaller males remain hornless. In this study we report on the alternative reproductive tactics used by males with these two morphologies, and present experimental and behavioural data suggesting that these alternative tactics selectively favour discretely different male phenotypes. Horned males aggressively defended tunnel entrances containing breeding females. Fights involved the use of horns, and males with longer horns were more likely to win fights. In contrast, hornless males employed nonaggressive sneaking behaviours when faced with competitively superior males. Sneaking behaviours appeared to require high degrees of manoeuvrability inside tunnels to access and mate with females despite the presence of a guarding male. Comparisons of running performances of males with identical body sizes but different horn lengths suggest that the possession of horns reduces male agility inside tunnels. Thus, horn possession confers a clear advantage to males using fighting behaviours to access females, whereas hornlessness may be favoured in males that rely primarily on sneaking behaviours. Combined, the two alternative reproductive tactics used by male O. taurus appear to favour opposite horn phenotypes, which may explain the paucity of intermediate morphologies in natural populations of O. taurus. },
	author = {Moczek, Armin P. and Emlen, Douglas J.}
}
@article {2092,
	title = {Intra- and intersexual interactions at breeding burrows in the horned beetle, Coprophanaeus ensifer},
	journal = {Animal Behavior},
	volume = {36},
	number = {3},
	year = {1988},
	pages = {741-748},
	abstract = {Coprophanaeus ensifer is a large horned beetle in which, in contrast to many other horned beetles, both males and females possess a long head horn. The species is a carrion feeder and has a developed nesting behaviour including provisioning the nest with larval food. Interactions between individuals at breeding burrows were observed in terraria. Both intra- and intersexual fights were common. In males fighting time was correlated with horn size. Although the horn size distribution of males was platykurtic there was no clear evidence of dimorphism in behaviour. Males tried to copulate with all females but only a few attempts with large females resulted in a copulation. All males actively tried to copulate but larger males were more successful. In each experiment individuals starting nesting behaviour were usually the largest ones. The significance of body and horn size is discussed with special emphasis on female horns and fighting behaviour.},
	author = {Otronen, Merja}
}
@article {2110,
	title = {Sexual selection and horn allometry in the dung beetle Euoniticelus intermedius},
	journal = {Animal Behavior},
	volume = {71},
	year = {2006},
	pages = {567-576},
	abstract = {Secondary sexual characters are often positively allometric, such that larger individuals of a species have proportionally larger traits. The sexually selected weapons found on many insect species, however, show declining allometric slopes with body size. Previous work on these curved allometric relations has focused on the role of competition for limited resources between growing body parts within pupae, but there is an alternative explanation that has received little attention: changes in the allometric slope may reflect changes in the fitness benefits associated with increases in horn size and body size change as an animal gets larger. The allometric curve of the horn of the male dung beetle Euoniticellus intermedius shows one of the largest declines in slope known and by setting up contests between males of similar, or different, sizes over access to females we were able to investigate the importance of horn and body size for males of different sizes and horn lengths. Both body size and horn size were important in determining contest outcome in small males, but horn size became more important as body size increased, so that in contests between large males it was by far the most important predictor of victory. These findings are consistent with theoretical predictions of how fitness functions can affect allometry and offer an alterna- tive to some of the previous verbal arguments made to explain positive allometry. },
	author = {Pomfret, Joanne C. and Knell, Robert J.}
}
