Social administration of juvenile hormone to larvae increases body size and nutritional needs for pupation

Social insects often display extreme variation in body size and morphology within the same colony. In many species, adult morphology is socially regulated by workers during larval development. While larval nutrition may play a role in this regulation, it is often difficult to identify precisely what larvae receive from rearing workers, especially when larvae are fed through social regurgitation. Across insects, juvenile hormone is a major regulator of development. In the ant Camponotus floridanus, this hormone is present in the socially regurgitated fluid of workers. We investigated the role the social transfer of juvenile hormone in the social regulation of development. To do this, we administered an artificial regurgitate to larvae through a newly developed handfeeding method that was or was not supplemented with juvenile hormone. Orally administered juvenile hormone increased the nutritional needs of larvae, allowing them to reach a larger size at pupation. Instead of causing them to grow faster, the juvenile hormone treatment extended larval developmental time, allowing them to accumulate resources over a longer period. Handfeeding ant larvae with juvenile hormone resulted in larger adult workers after metamorphosis, suggesting a role for socially transferred juvenile hormone in the colony-level regulation of worker size over colony maturation.

The Role of Stomach Infrastructures on Children's Work and Child Labour in Africa: Systematic Review

Child labour remains a prevalent global concern, and progress toward eradicating harmful children's work appears to have stalled in the African continent and henceforth, integrated social policy intervention is still required to address the problem. Among several forms of social policy interventions, stomach infrastructure (i.e., in-kind and/or cash transfers) have been a key policy approach to support vulnerable families to lighten households' resources burden, which forces them to consider child labour as a coping strategy. There is growing evidence on the impacts of these programs in child labour. However, this evidence is often mixed regarding children's work outcomes, and the existing studies hardly describe such heterogeneous outcomes from the child-sensitive approach. To this end, a systematic literature search was conducted for studies in African countries. From 743 references retrieved in this study, 27 studies were included for the review, and a narrative approach has been employed to analyse extracted evidence. Results from the current study also demonstrate a mixed effect of in-kind and cash transfers for poor households on child labour decisions. Hence, the finding from the current review also demonstrates a reduced participation of children in paid and unpaid work outside the household due to in-kind and cash transfers to poor households, but children's time spent in economic and non-economic household labour and farm and non-farm labour, which are detrimental to child health and schooling, has been reported increasing due to the program interventions. The question remains how these programs can effectively consider child-specific and household-related key characteristics. To this end, a child-sensitive social protection perspective has been applied in this study to explain these mixed outcomes to inform policy design.

Potential for Use of Erythritol as a Socially Transferrable Ingested Insecticide for Ants (Hymenoptera: Formicidae)

Ants are significant structural and agricultural pests, generating a need for human-safe and effective insecticides for ant control. Erythritol, a sugar alcohol used in many commercial food products, reduces survival in diverse insect taxa including fruit flies, termites, and mosquitos. Erythritol also decreases longevity in red imported fire ants; however, its effects on other ant species and its ability to be transferred to naïve colony members at toxic doses have not been explored. Here, we show that erythritol decreases survival in Tetramorium immigrans Santschi (Hymenoptera: Formicidae) in a concentration-dependent manner. Access to ad-libitum water reduced the toxic effects of erythritol, but worker mortality was still increased over controls with ad-lib water. Foraging T. immigrans workers transferred erythritol at lethal levels to nest mates that had not directly ingested erythritol. Similar patterns of mortality following erythritol ingestion were observed in Formica glacialis Wheeler (Hymenoptera: Formicidae), Camponotus subarbatus Emery (Hymenoptera: Formicidae), and Camponotus chromaiodes Bolton (Hymenoptera: Formicidae). These findings suggest that erythritol may be a highly effective insecticide for several genera of ants. Erythritol's potential effectiveness in social insect control is augmented by its spread at lethal levels through ant colonies via social transfer (trophallaxis) between workers.