Do Tetranychus urticae males avoid mating with familiar females?

Abstract

The two-spotted spider mite, Tetranychus urticae, usually lives in kin groups under common webs. Because only the first mating results in fertilisation in female T. urticae, adult males guard quiescent deutonymph females, those at the stage immediately before maturation, to ensure paternity. Therefore, the cost of precopulatory guarding time seems considerable for males. Moreover, the fitness indices of daughters from intra-population crosses were significantly lower than those of daughters from inter-population crosses, indicating that inbreeding depression exists in T. urticae. Therefore, we hypothesised that T. urticae males should be choosy in guarding familiar females to avoid inbreeding depression. Furthermore, webs should be a key element of the environment shared by familiar individuals. In this study, we demonstrated the inbreeding avoidance mechanism of T. urticae males in relation to webs produced by familiar females (known webs) or unfamiliar females (unknown webs). Regardless of surrounding webs (known or unknown), males preferred unfamiliar to familiar females. We further examined whether males detect unfamiliar females by their webs. When males had experienced a female's web without encountering that female, they subsequently preferred females that did not produce the surrounding webs in which the choice experiment was conducted. Results suggest that putative kin recognition for inbreeding avoidance in T. urticae males is based on the relationship between webs and females, and not on the discrimination of webs in shared environments.

Molecular Diversity of Two-Spotted Spider Mite (Tetranychus urticae) in Apple Orchards Across Poland and its Potential Link with the Resistance to Meti-Acaricides

“…However, the investigation on the mechanism of gene flow of the two-spotted spider mite in apple orchards proved that high population density increases the migration rate among spatially distant breeding colonies ). Additionally, the evidence for inbreeding-avoidance behavior in dense populations of T. urticae has been found by Yoshioka and Yano (2014). Hence, high density of population during sample collection time, where outbreeding and gene flux are unconstrained more likely than among distant populations, together with the mixed origin of specimens within population, may provide an explanation for the genetic divergence observed herein.…”

Kin competition accelerates experimental range expansion in an arthropod herbivore

“…; Clotuche et al . ; Yoshioka & Yano ). Importantly, kin recognition has been shown to play an important role in condition‐dependent dispersal (Bitume et al .…”

Spider mite mothers adjust reproduction and sons' alternative reproductive tactics to immigrating alien conspecifics

“…Uninfected Y-males were superior mates to both uninfected Y- and Cardinium -infected G-females, but there were no apparent incompatibilities between mates of the two populations, no distorted sex ratio or decreased egg hatchability, that could be assigned to Cardinium infection in males of the G-population. Rather than mediated by Cardinium , the positive effect of Y-males on the reproduction of females from both populations was caused by interpopulation differences in in- and out-breeding depression/advantages arising from differences in intrapopulation inbreeding levels [51–53]. Judged from the number of eggs produced by mating with own or alien males, Y-females had an inbreeding, yet G-females an outbreeding, advantage.…”

“…Chemosensory and/or visual cues on G-individuals or their webbing may have exerted positive effects on feeding behaviour and resulting oviposition by females of both populations. The webbing by spider mites is considered an important source of information and spider mites are known to possess sophisticated abilities to discriminate conspecific webs based on population origin [31], life stage [32] or familiarity [53]. Non-leaf-mediated effects of genetic relatedness and density (via physical contact between individuals or the web) on the dispersal behaviour of T. urticae were shown by Bitume et al [59].…”