The evolution of parental care in insects: the roles of ecology, life history and the social environment

Abstract

Parental care increases the fitness of offspring at a cost to the parents in terms of residual reproductive success. This trade‐off may be affected by ecology, life history and the social environment, which raises the question as to how these factors contribute to the evolution of parental care. Here, previous hypotheses concerning the evolution of parental care in insects are summarized and discussed and the underlying empirical evidence is reviewed. Ecological factors such as harsh environments, ephemeral food sources or predation pressure are broadly accepted as evolutionary drivers of parental care. The most consistent evidence supports a role for natural enemies such as predators, microbes and cannibalistic conspecifics. Also, the importance of ecological factors may interact with the life history (parity) of a species, either as a pre‐adaptation facilitating the evolution of parental care or as a consequence of enhanced parental investment under parental care. Yet, only limited experimental research has been carried out to test the combined influence of ecology and life history in the evolution of parental care. Several forms of care can mediate the transition from solitary to family living, which entails the emergence of a novel – social – environment that generates new selection pressures from interactions within and between families. In this context, we review examples of studies on communal breeding, brood parasitism, parent–offspring conflict and co‐adaptation, and discuss how these social interactions may in turn be influenced by ecological factors such as food availability or population density. Insects are uniquely suitable for experimental and comparative research on the complex interplay between ecology, life history, and the social environment.

Short-term benefits, but transgenerational costs of maternal loss in an insect with facultative maternal care

“…This notwithstanding, both scenarios emphasize that the parental presence can be associated with costs for the tended offspring (see also [21]), which emerge when the (laboratory) conditions do not allow (variation in) the benefits of parental care to be revealed. These findings overall indicate that as long as parental care only has limited effects on offspring development and survival (a scenario that presumably prevailed in the early evolution of family life), it is likely that the emergence and maintenance of parental investment into post-hatching care mostly relies on the benefits of parenting behaviours that enable offspring to better cope with environmental constraints, such as limited food access or the presence of pathogens and predators [2,3].…”

“…These benefits mostly derive from the expression of parenting behaviours [1,2] such as nest construction, brood/ juvenile attendance or food provisioning [2,3], and are thus contingent on the parental presence. Consequently, parental loss, e.g.…”

Manipulation of parental nutritional condition reveals competition among family members

“…Parental care and its evolution have continually received attention from scientists of diverse fields over the past few years. Parental care, in its wider sense, includes all traits expressed by parents that enhance the fitness of their offspring, including the production of nutritious eggs, the guarding of the nest site or food provisioning (Clutton‐Brock, ; Gross, ; Smiseth et al ., ; Wong et al ., ). However, caring for young is thought to be costly for parents and the energy invested in current offspring often goes hand in hand with fewer resources available for somatic or mating efforts and hence for future offspring (Alonso‐Alvarez & Velando, ).…”

Influences of Relatedness, Food Deprivation, and Sex on Adult Behaviors in the Group‐living InsectForficula auricularia

“…; Wong et al. ). The emergence and persistence of these multiple forms of group living in nature generally rely on the fact that the benefits a social system provides to group members outweigh its associated costs (reviewed in Krause & Ruxton ; Bourke ).…”