Alteration of gut microbiota with a broad‐spectrum antibiotic does not impair maternal care in the European earwig

Abstract

The microbes residing within the gut of an animal host often increase their own fitness by modifying their host's physiological, reproductive, and behavioural functions. Whereas recent studies suggest that they may also shape host sociality and therefore have critical effects on animal social evolution, the impact of the gut microbiota on maternal care remains unexplored. This is surprising, as this behaviour is widespread among animals, often determines the fitness of both juveniles and parents, and is essential in the evolution of complex animal societies. Here, we tested whether life-long alterations of the gut microbiota with rifampicin -a broad-spectrum antibiotic -impair pre-and post-hatching maternal care in the European earwig. Our results first confirm that rifampicin altered the mothers' gut microbial communities and indicate that the composition of the gut microbiota differs before and after egg care. Contrary to our predictions, however, the rifampicin-induced alterations of the gut microbiota did not modify pre-or post-hatching care. Independent of maternal care, rifampicin increased the females' feces production and resulted in lighter eggs and juveniles. By contrast, rifampicin altered none of the other 21 physiological, reproductive and longevity traits measured over the 300 days of a female's lifetime. Overall, these findings reveal that altering the gut microbiota with a large spectrum antibiotic such as rifampicin does not necessarily affect host sociality. They also emphasize that not all animals have evolved a co-dependence with their microbiota and call for caution when generalizing the central role of gut microbes in host biology.

Cadmium does not affect post-hatching maternal care or early offspring development in earwigs

“…In honeybees, for instance, cadmium exposure alters the microbiome and some bacterial strains can bioaccumulate this pollutant, making bees more resilient to cadmium (Rothman et al 2019). Investigating the microbiome composition (Van Meyel, Devers, Dupont, et al 2021) and its putative role in earwig cadmium resistance would be of great value.…”

Research Progresses on the Function and Detection Methods of Insect Gut Microbes

“…In addition, antibiotics are frequently used to prevent bacterial infection of larval honeybees, but prolonged use of antibiotics leads to disruption of gut microbial homeostasis, increasing susceptibility to opportunistic pathogens and affecting honeybee health [ 76 ]. Meyel et al found that after feeding on rifampicin by European earwig larvae, the homeostasis of the host’s gut microbes was disrupted, and the weight of eggs and larvae decreased [ 77 ]. Powell et al found that Apis mellifera ingested tylosin tartrate, which significantly increased their susceptibility to S. marcescens [ 78 ].…”

The costs and benefits of maternal egg care in the earwig Forficula pubescens

“…(3) We measured the level of egg defence just after the video recording. Egg defence represents the mother's endurance in defending her clutch and herself against predators (Van Meyel et al 2021). This was measured by gently opening each Petri dish, standardly poking the pronotum of the mother with a glass capillary (1 poke per second) and then recording the number of pokes required for her to move more than one body length away from its initial position.…”