Divergent effects ofWolbachiaon host temperature preference

Abstract

ABSTRACTHeritable symbionts can modify a range of ecologically important host traits, including behavior. About half of all insect species are infected with maternally transmittedWolbachia, a bacterial endosymbiont known to alter host reproduction, nutrient acquisition, and virus susceptibility. Here, we broadly test the hypothesis thatWolbachiamodify host behavior by assessing the effects of eight differentWolbachiastrains on the temperature preference of sixDrosophila melanogaster-subgroup species. Four of the seven host genotypes infected with A-groupWolbachiastrains (wRi inD. simulans, wHa inD. simulans, wSh inD. sechellia, andwTei inD. teissieri) prefer significantly cooler temperatures relative to uninfected genotypes. Contrastingly, when infected with divergent B-groupwMau,D. mauritianaprefer a warmer temperature. For most strains, changes to host temperature preference do not alterWolbachiatiter. However, males infected withwSh andwTei experience an increase in titer when shifted to a cooler temperature for 24 hours, suggesting thatWolbachia-induced changes to host behavior may promote bacterial replication and influenceWolbachiatransmission rates. Modifications to host temperature preference likely influence host thermoregulation, and understanding the fitness consequences of these effects is crucial for predicting evolutionary outcomes of host-symbiont interactions, including howWolbachiaspread to become common.