Caring males do not respond to cues about losses in paternity in the burying beetle Nicrophorus vespilloides

In species with biparental care, males may be under selection to adjust the amount of care they provide for their offspring in response to losses in paternity. Previous work on birds and fishes provide mixed empirical evidence for facultative adjustments in male care to losses in paternity. One potential reason for this inconsistency is that males need access to reliable cues of losses in paternity, and that it might be difficult to assess what cues, if any, are used by males. Here we manipulated three cues of losses in paternity in the burying beetle Nicrophorus vespilloides: the presence of a (dead) rival male (N = 44), the temporary absence of the female (N = 41) and the presence of a rival male's cuticular hydrocarbons on the female (N = 44). We focused on these three cues because there is evidence that males respond to these cues in other species and there is also evidence that our study species responds to these cues in other contexts. We found no effect of the three cues on the amount of direct or indirect care provided by the male, male weight change, or the number and weight of offspring. Our results provide no evidence that single male parents adjust their investment in the current brood based on cues of losses in paternity. As previous work showed that most wild females arriving on a carcass already store sperm, it is likely that males have evolved a fixed response to female polyandry by mating very frequently with the female.