A positive correlation between the parental effort of a male and female should promote stable biparental care. In order to prevent infanticide male and female burying beetles are said to guard against intruders cooperatively and the presence of a male partner is said to increase the probability of successful defence. However, this hypothesis is supported only by indirect evidence. In this study this hypothesis is tested by direct observation. Whether the intruder was male or female, contests between the same and the opposite sex occurred, although there were few contests between resident females and intruding males. In addition, resident pairs tended to win irrespective of the sex of the intruder, although it is reported that among burying beetles large beetles usually win intra-sexual contests. In the presence of a partner, a small resident can defend a carcass against a large con-sexual intruder. These results suggest that by means of biparental cooperation burying beetles can repel stronger intruders and supports the hypothesis that the threat of infanticide is the primary explanation for extended biparental care in these beetles. and Seizi Suzuki.
Hrobaříci jsou malá skupina brouků patřící do čeledi mrchožroutovití (Silphidae), která má na světě okolo 190 druhů. Centrem jejich rozšíření je palearktická oblast. Mezi hrobaříky ale najdeme jak zástupce s rozsáhlým areálem výskytu, tak i druhy endemické. Tito brouci žijí na různých biotopech, ale jsou si vzhledově podobní. Vyvinula se u nich naprosto jedinečná péče o potomstvo, kdy se dospělci starají o své larvy. Ze způsobu života hrobaříků a vzájemných potravních vztahů tak přímo vyplývá význam a užitečnost těchto brouků. Odklízením mršin a urychlováním rozkladných procesů jsou velmi prospěšní., Burying beetles are a small group of beetles, belonging to the carrion beetle family (Silphidae), which has around 190 species worldwide. The centre of their distribution is the Palearctic region. While some species are widely distributed, others are endemics with narrow distribution range. Burying beetles live in different habitats, but they are phenotypically similar. They also have developed unique care for offspring when adults care for their larvae. Their necrophore way of life and mutual food relationships directly highlight the importance and usefulness of these beetles. The major ecological importance of burying beetles lies in the removal of carcasses and acceleration of degradation processes., and Jan Schneider.
Ptomascopus morio of both sexes are attracted to vertebrate carcasses, a necessary resource for reproduction. The stage during reproduction that resource defense was most intense and the hypothesis that large beetles were better competitors and sired a larger share of the offspring were supported and tested. Male-male aggression (pushing, biting and mounting) was commonly observed before and during oviposition, but rarely after the larvae hatched. Few female-female aggressive interactions were observed at any time. Parentage analysis of the offspring of six groups of two males and two females each reproducing on a separate carcass revealed that the large males sired more of the offspring than small males. Paternity analysis, using AFLP markers, revealed that larger males had higher paternity than smaller males, but the number of eggs produced by each female did not differ between large and small females. This suggests that competition among males is intense until the end of oviposition and that resident (large) males can acquire more mates and sire more offspring than smaller males; competition among females was not evident at any time.
Nicrophorine beetles use small vertebrate carrion for breeding resource. While Nicrophorus spp. have highly developed biparental care, no form of parental care is recorded for Ptomascopus spp. We examined two effects of resource guarding by Ptomascopus morio. The presence of parents, especially the female, reduced the number of fly larvae on chicken carrion. Parents also enhanced the survival of brood faced with predation by the rove beetle, Ontholestes gracilis. In 6 out of 20 trials, the rove beetle predators were killed by Ptomascopus morio parents. We conclude that Ptomascopus morio has a simple, and possibly primitive form of parental care.