Responses of Second-Instar Male Nymphs of Four Mealybug Species (Hemiptera: Pseudococcidae) to Conspecific and Heterospecific Female Sex Pheromones

Abstract

The response of the late second-instar male nymphs of the mealybug species (Hemiptera, Pseudococcidae), Planococcus citri (Risso), Planococcus ficus (Signoret), Pseudococcus cryptus Hempel Nipaecoccus viridis (Newstead), to their conspecific and heterospecific female pheromone was studied. Males that exhibited the typical appearance of late-second-instar nymphs were tested. The male behavior was monitored soon after their exposure to the tested female sex pheromone in glass Petri dish arenas. Male nymph behavior toward the pheromone source was characterized based on their aggregation on the disks in the arena. Males of all four tested mealybug species were attracted to their conspecific female pheromone. By contrast, almost no interceptions of male nymphs with disks impregnated with a heterospecific female pheromone were observed. The mode of attraction of each of male nymphs of P. ficus, among most of the tested individuals (>80%), to the conspecific female sex pheromone, (S)-lavandulyl senecioate and or (S)-lavandulyl isovalerate, was the same as the mode of attraction latter on as adult. We suggest that by being attracted to the conspecific pheromone these males may direct themselves to a suitable pupation site near conspecific non-sibling mature females, thus preventing inbreeding. The repellency of heterospecific sex pheromone to males that are looking for a pupation site suggests that the latter try to avoid close contact with heterospecific females.Keywords Mealybug . male nymphs . sex pheromone . attraction J Insect Behav (2012) 25:504-513

Evidence for Gene Flow between Two Sympatric Mealybug Species (Insecta; Coccoidea; Pseudococcidae)

“…The occurrence of P. citri males attracted to lavandulyl isovalerate, i.e., LI males, among the East Mediterranean population of P. citri ( Table 4 ) suggests a recent gene flow from P. ficus to P. citri in this particular area. Lavandulyl isovalerate is a pheromone compound produced by P. ficus populations, and P. ficus males attracted to it were found only in East Mediterranean populations, as in the course of the present study as well as in previous research [31] , [32] , [87] .…”

Ecology of female mating failure/lifelong virginity: a review of causal mechanisms in insects and arachnids

“…In many instances, low female mating probability on a given day coincides with rarity of males (Calabrese & Fagan, ; Franco et al., ; Calabrese et al., ; Rhainds, ; Fauvergue, ; Faust & Forrest, ; Sciarretta et al., ). These studies support widely held views of female‐biased sex ratios and/or acute shortage of males (‘male vacuum’) as triggers of FMF (Wing, ; Mendel et al., ; Fritzsche et al., ). As expected, the level of female choosiness declines as the sex ratio becomes female biased (Monier et al., ).…”

“…Host plants directly affect outcomes of competitive interactions for access to males either as a physical substrate of vibration sexual signals (Cocroft & Rodríguez, ; Laumann et al., ), as resource in mating aggregations (Papadopoulos et al., ; Xu et al., ), or as sources of volatiles that synergize attraction of males to female‐produced sex pheromone (Dekker & Barrozo, ). In pupal mating butterflies (Lepidoptera: Nymphalidae), foraging males locate sessile female pupae using cues associated with previous defoliation caused by feeding larvae (Estrada & Gilbert, ), highlighting a behavioral carryover effect of pupation site (Gentry, ; Mendel et al., ). In insects with neotenic females, female late instars seek pupation sites that alleviate the risk of FMF among emergent adults: mating probability often increases with the height position of females on host plants, illustrating behavioral adaptation of larval females with fitness consequences across developmental stages (Rhainds et al., ).…”

“…However, protogyny is correlated with extended longevity of females (which counterbalances the risk of FMF; Degen et al, 2015Degen et al, , 2017 and may in fact enhance mating success of early emergent females by reducing lateseason signal competition among conspecifics (Rhainds, 2018). Sex-specific pupation behavior of male and female larvae may affect emergence time and maintain protandry independent of environmental conditions: in fireflies, for example, pupation of male late instars on light-exposed substrates as opposed to females pupating in shaded locations is sufficient in itself to maintain protandry (Gentry, 2003;Mendel et al, 2012).…”

Attractiveness of Harlequin Bug, Murgantia histrionica, Aggregation Pheromone: Field Response to Isomers, Ratios, and Dose

“…Presumably, starved nymphs use the pheromone to assist location of host plants. Late-instar nymphs also find potential mates at plants occupied by conspecifics, as is the case, for instance in immature male mealybug response to female sex pheromone (Mendel et al 2012). The nymphal numbers recovered in the blend trial precluded examination of the subtleties of their response to isomer ratios.…”