Alloparental caregiving is key to humans’ highly flexible reproductive strategies. Across species and across societies, alloparental care is more common in harsh and/or unpredictable environments (HUEs). Currently, however, it is unclear whether HUEs predict intra-population variation in alloparental care, or whether early life HUEs might predict later alloparental care use in adulthood, consistent with adaptive developmental plasticity. We test whether harshness measures (socioeconomic status (SES), environmental hygiene, crowding) and unpredictability measures (parental unemployment, paternal absence, household moves) predicted how much alloparental assistance families in Cebu, Philippines received, in a multigenerational study with data collected across four decades. Though worse environmental hygiene predicted more concurrent alloparental care in 1994, we found little evidence that HUEs predict within-population variation in alloparental care in this large-scale, industrialized society. Indeed, less-crowded conditions and higher SES predicted more alloparental care, not less, in the 1980s and in 2014 respectively, while paternal absence in middle childhood predicted less reliance on alloparental care in adulthood. In this cultural context, our results generally do not provide support for the translation of interspecific or intersocietal patterns linking HUEs and alloparental care to intra-population variation in alloparental care, nor for the idea that a reproductive strategy emphasizing alloparental care use may be preceded by early life HUEs.

Parasitoid wasps are key agents for controlling insect pests in integrated pest management programs. Although many studies have revealed that the behavior of parasitic wasps can be influenced by insecticides, the strategies of patch time allocation and oviposition have received less attention. In the present study, we forced the endoparasitoid Meteorus pulchricornis to phoxim exposure at the LC30 and tested the foraging behavior within patches with different densities of the host, the larvae of the tobacco cutworm Spodoptera litura. The results showed that phoxim treatment can significantly increase the patch-leaving tendency of female wasps, while host density had no impact. The number of oviposition and the number of previous patch visits also significantly influenced the patch time allocation decisions. The occurrence of oviposition behavior was negatively affected by phoxim exposure; however, progeny production was similar among patches with different host densities. Phoxim exposure shaped the offspring fitness correlates, including longer durations from cocoon to adult wasps, smaller body size, and shorter longevity. The findings of the present study highlight the sublethal effects that reduce the patch residence time and the fitness of parasitoid offspring, suggesting that the application of phoxim in association with M. pulchricornis should be carefully schemed in agroecosystems.

The establishment of an invasive species depends on reproductive success and dispersion capability in the new environment. One of the striking examples of invasion in urban environments is the mosquito Aedes aegypti Linnaeus, 1762 (Culicidae). The success of this species is primarily attributed to its ability to colonize urban environments, and some of the important adaptive strategies associated with this ability is the preference for humans as a blood source and intense occupation of residential (indoor) environments. This study evaluated the effects of location (indoor vs. outdoor) and water nutrient level (% organic matter) on the oviposition preference of A. aegypti in an urban environment. We used oviposition choice experiments to evaluate mosquito oviposition in containers holding 1:1 vs 1:0 ratios of water: organic matter placed indoors and outdoors. Eggs were sampled once per week for nine weeks. Our results revealed a strong oviposition preference for outdoor containers, with a significant preference for containers with higher concentrations of organic matter during the fifth to ninth weeks. However, mosquitoes occupying indoor environments did not prefer to lay eggs in containers with lower levels of organic matter. A better understanding of the preferences of A. aegypti regarding the nutrient level and location of oviposition containers can increase our understanding of the behavioral factors allowing mosquitoes to utilize anthropogenic environments.

Recently, researchers investigating the origins of domestication have debated the significance of resource intensification in the shift from foraging to food production. In eastern North America, one of several independent centers of domestication, this question remains open. To determine whether initial domestication may have been preceded by intensification in eastern North America at approximately 5000 cal BP, I evaluated the archaeofaunal assemblages from six sites in the middle Tennessee River valley. Analyses of these data suggest that overall foraging efficiency gradually declined prior to initial domestication, but patch-specific declines in foraging efficiency occurred in wetland habitats and not terrestrial ones. Climatic warming and drying during the Middle Holocene, growing human populations, and oak-hickory forest expansion were the likely drivers of these changes in foraging efficiency. These results support the hypothesis that initial domestication in eastern North America was an outcome of intensification driven by environmental change and human population increases. Finally, while the debate concerning the relationship of intensification to domestication has been framed in terms of a conflict between niche construction theory and optimal foraging theory, these perspectives are compatible and should be integrated to understand domestication more fully.

Optimization models have often been useful in attempting to understand the adaptive significance of behavioral traits. Originally such models were applied to isolated aspects of behavior, such as foraging, mating, or parental behavior. In reality, organisms live in complex, ever-changing environments, and are simultaneously concerned with many behavioral choices and their consequences. This target article describes a dynamic modeling technique that can be used to analyze behavior in a unified way. The technique has been widely used in behavioral studies of insects, fish, birds, mammals, and other organisms. The models use biologically meaningful parameters and variables, and lead to testable predictions. Limitations arise because nature's complexity always exceeds our modeling capacity.

The transfer of food among group members is a ubiquitous feature of small-scale forager and forager-agricultural populations. The uniqueness of pervasive sharing among humans, especially among unrelated individuals, has led researchers to evaluate numerous hypotheses about the adaptive functions and patterns of sharing in different ecologies. This article attempts to organize available cross-cultural evidence pertaining to several contentious evolutionary models: kin selection, reciprocal altruism, tolerated scrounging, and costly signaling. Debates about the relevance of these models focus primarily on the extent to which individuals exert control over the distribution of foods they acquire, and the extent to which donors receive food or other fitness-enhancing benefits in return for shares given away. Each model can explain some of the variance in sharing patterns within groups, and so generalizations that ignore or deny the importance of any one model may be misleading. Careful multivariate analyses and cross-cultural comparisons of food transfer patterns are therefore necessary tools for assessing aspects of the sexual division of labor, human life history evolution, and the evolution of the family. This article also introduces a framework for better understanding variation in sharing behavior across small-scale traditional societies. I discuss the importance of resource ecology and the degree of coordination in acquisition activities as a key feature that influences sharing behavior.