Sexual conflict arises in biparental species because of the fitness payoffs of shifting the
costs of care onto their partner. The negotiation model asserts that parents actively monitor their
partner’s level of investment and adjust their own in response generally resulting in partial
compensation when a member of the pair reduces their level of investment. The willingness of one
parent to compensate for the other’s change is found to be widely variable. Habitat or resource
quality available to pairs may explain such variation. It is predicted that the level of compensation
by one partner will increase with decreasing resource quality. I tested this prediction with the
biparental burying beetle, Nicrophorus orbicollis. Under natural conditions, burying beetles apply
costly social immune molecules to carcasses of small vertebrates to preserve nutritional value for
young. The goals of this research were (1) to determine if males immunologically compensate
when females are immunologically handicapped; and (2) determine the impact of resource quality
on compensation. Changes in lysozyme-like-activity (LLA) and phenoloxidase (PO) production
in oral and anal secretions were used to quantify social immune investment. Pairs were provided
a mouse carcass of one of three qualities: freshly thawed, aged for 3 days, or aged for 7 days. As
expected, female LLA decreased once injected with lipopolysaccharide (LPS) irrespective of
carcass quality. Injections caused significant down regulation of oral PO in females. Male LLA
increased as the quality of carcasses decreased when paired with handicapped females. Males
showed no changes in PO across treatments or carcass types. My results demonstrate that males
compensate for a change in maternal investment and the level of compensation increases as
resource quality decreases.