Carcass Fungistasis of the Burying BeetleNicrophorus nepalensisHope (Coleoptera: Silphidae)

Abstract

Our study investigated the fungistatic effects of the anal secretions ofNicrophorus nepalensisHope on mouse carcasses. The diversity of fungi on carcasses was investigated in five different experimental conditions that corresponded to stages of the burial process. The inhibition of fungal growth on carcasses that were treated by mature beetles before burial was lost when identically treated carcasses were washed with distilled water. Compared with control carcasses, carcasses that were prepared, buried, and subsequently guarded by mature breeding pairs of beetles exhibited the greatest inhibition of fungal growth. No significant difference in fungistasis was observed between the 3.5 g and the 18 to 22 g guarded carcasses. We used the growth of the predominant species of fungi on the control carcasses,Trichodermasp., as a biological indicator to examine differences in the fungistatic efficiency of anal secretions between sexually mature and immature adults and between genders. The anal secretions of sexually mature beetles inhibited the growth ofTrichodermasp., whereas the secretions of immature beetles did not. The secretions of sexually mature females displayed significantly greater inhibition of the growth ofTrichodermasp. than those of sexually mature males, possibly reflecting a division of labor in burying beetle reproduction.

Burying beetles regulate the microbiome of carcasses and use it to transmit a core microbiota to their offspring

“…Naturally decomposing cadavers (without Nicrophorus beetles) are dominated by endogenous mouse‐associated bacteria, and later stages are dominated by soil‐borne bacteria (Evans, ; Metcalf et al., ). During carcass preparation, carrion beetles often remove the intestine of the host cadaver (Hwang & Lin, ; Pukowski, ), to reduce colonization of carcasses by host endogenous gut bacteria. This could be another reason why beetle‐prepared carcasses did not support the growth of anaerobic bacterial communities often encountered in decomposing carcasses, where they are likely to originate from the cadaver's intestinal microbiota (Metcalf et al., ).…”

Fitness costs associated with building and maintaining the burying beetle’s carrion nest

“…Carcass maintenance includes making and applying antimicrobial anal exudates, and patrolling the carcass for fly eggs. Of these two activities, we know that females contribute more to antimicrobial maintenance activities 8 22 , and this may explain why only female residual fitness was correlated with carcass roundness while male residual fitness was not. This interpretation of the data implies that males drive the correlation between carcass roundness and residual female fitness.…”

A Potential Collective Defense of Drosophila Larvae Against the Invasion of a Harmful Fungus

“…By separating group size from density effects, our results suggest that non-(eu)social D. melanogaster fruit fly larvae harbor the potential to collectively suppress the invasion of a harmful filamentous fungus. It has been repeatedly stated that collective actions that keep harmful microbes in check are not limited to eusocial insects or those with sophisticated parental care in small family groups (Biedermann and Taborsky, 2011;Hwang and Lin, 2013;Meunier, 2015). On the contrary, it is assumed that collective actions have their evolutionary origin in comparatively simple semi-social aggregation behaviors, such as the Drosophila system, which lack comparatively complex behavioral structuring, nest building, and altruism (Meunier, 2015;Biedermann and Rohlfs, 2017).…”