Effects of predation risk on mating behavior of the Kanzawa spider mite

Abstract

In the Kanzawa spider mite, Tetranychus kanzawai, adult males locate pre-reproductive quiescent females and engage in precopulatory mate guarding. We found that re-reproductive quiescent females preferred to be near veins, rather than other leaf parts, and moreover, adult males spent more time along the vein than on other parts. Consequently, T. kanzawai males found more quiescent females along veins than those on other parts. However, the predatory mite Neoseiulus womersleyi also found more quiescent T. kanzawai females along veins than those on other parts. Moreover, N. womersleyi found more guarding males than solitary males of T. kanzawai. Thus, we experimentally examined the effects of predation risk on the mating behavior of T. kanzawai. The presence of N. womersleyi reduced T. kanzawai female preference for vein vicinity as a quiescent site. Although the predation risk of guarding T. kanzawai males was lower than that of solitary males after detection by predators, the presence of N. womersleyi also reduced the proportion of guarding T. kanzawai males. These results suggest that the possible benefits of preferring vein vicinity as quiescent sites by T. kanzawai females is outweighed by predation risk in the presence of predators, and that the risk of detection by predators would be more important for T. kanzawai males than the risk of being preyed upon.

Effects of density experience on mate guarding behavior by adult male Kanzawa spider mites

“…To clarify this possibility, future studies should examine whether mounting is more costly to T. kanzawai males than attending behavior. Oku and Yano (2008) observed only mounting behavior as precopulatory mate guarding; however, most of T. kanzawai adult males guarded quiescent females. One reason for this result may be that in their experiments, Oku and Yano (2008) kept more than 50 males on the same leaf disc until they were used.…”

“…Contact mate guarding is more effective in ensuring the reproductive success of males than non-contact mate guarding (e.g., Singer 1987;Convey 1989). However, contact mate guarding is sometimes energetically costly to males (Plaistow et al 2003;Saeki et al 2005;Sparkes et al 1996) and conspicuous to predators (Zeiss et al 1999;Cothran 2004;Oku and Yano 2008). Therefore, in species which use both contact and non-contact mate guarding, it is expected that males should change mate guarding behavior in response to their circumstances.…”

“…I then introduced one male onto each leaf square with one quiescent deutonymph female, alternating males from the four groups, and kept them under laboratory conditions. I used only the leaf squares on which quiescent deutonymph females had settled along veins because T. kanzawai males find more quiescent deutonymph females along veins than on the rest of the leaf area (Oku and Yano 2008). After 3 h, I recorded the behavioral situation of the males.…”

“…According to the scenario described above, it has been predicted that males of tetranychid mites mount quiescent deutonymph females in the presence of rivals, while males attend quiescent females in the absence of rivals. However, in a previous study, most Tetranychus kanzawai males mounted quiescent females even when rivals were absent (Oku and Yano 2008).…”

Detection of predator cues alters mating tactics in male wolf spiders

“…In fact, several predator cues alter mating tactics in male wolf spiders 575 studies have demonstrated that males differentially use mating tactics based upon the detection of predators or perceived risk of predatory eavesdroppers (Endler, 1987;Reynolds et al, 1993;Godin, 1995;Oku & Yano, 2008); and that males adopting less conspicuous mating tactics experience lower predation risk (Cade, 1979;Howard, 1984;Larison, 2007). We explore whether predation costs associated with predatory eavesdropping heterospecifics could influence mating tactic expression in the wolf spider Rabidosa punctulata.…”