Do natural container habitats impede invader dominance? Predator-mediated coexistence of invasive and native container-dwelling mosquitoes

Abstract

Predator-mediated coexistence of competitors occurs when a species that is superior in competition is also more vulnerable to a shared predator compared to a poorer competitor. The invasive mosquito Aedes albopictus is usually competitively superior to Ochlerotatus triseriatus. Among second instar larvae, A. albopictus show a lesser degree of behavioral modiWcation in response to waterborne cues from predation by the larval midge Corethrella appendiculata than do O. triseriatus, rendering A. albopictus more vulnerable to predation by C. appendiculata than O. triseriatus. The hypothesis that C. appendiculata predation favors coexistence of these competitors predicts that C. appendiculata abundances will be negatively and positively correlated with A. albopictus and O. triseriatus abundances, respectively, and that coexistence will occur where C. appendiculata are common. Actual abundances of O. triseriatus, A. albopictus, and C. appendiculata in three habitats Wt this prediction. In natural container habitats like tree holes, C. appendiculata were abundant and competitors co-existed at similar densities. In cemeteries and tires, which occur primarily in nonforested, human-dominated habitats, A. albopictus dominated, with abundances twice those found in tree holes, but C. appendiculata and O. triseriatus were rare or absent. We also tested for whether antipredatory behavioral responses of A. albopictus differed among habitats or populations, or were correlated with local C. appendiculata abundances. We could detect no differences in A. albopictus antipredatory behavioral responses to water-borne cues from predation. Tree hole habitats appear to promote co-existence of O. triseriatus and A. albopictus through interactions with predatory C. appendiculata, and this predator effect appears to limit invasion success of A. albopictus in tree holes. There are many studies on predator-mediated coexistence in natural habitats but to our knowledge this is the first study to suggest differential predator-mediated coexistence between natural and man-made habitats.

Geographic Variation of Photoperiodic Diapause but Not Adult Survival or Reproduction of the Invasive MosquitoAedes albopictus(Diptera: Culicidae) in North America

“…Hence, high larval and, more importantly, almost complete adult mortality because of cold winter temperatures in the north are absent in the south, where Ae. albopictus is likely limited by factors impinging solely on immature survival, such as interspecific competition or predation at the larval stage and the desiccation and thermal tolerance of eggs (Juliano et al 2002, Kesavaraju et al 2008). …”

Predation resistance does not trade off with competitive ability in early-colonizing mosquitoes

“…Less competitive plant species are predicted to allocate resources instead to greater chemical or physical defenses against herbivory (Viola et al 2010). In animal species, greater competitive ability is generally associated with greater foraging effort, movement, and more rapid growth at low food availability (Wellborn et al 1996, Wissinger et al 1999, Kesavaraju et al 2008). However, this greater foraging effort and movement often attracts the attention of predators and lowers the predator vigilance of the prey species (Wissinger et al 1999, Kesavaraju et al 2008), thus making these superior competitors more susceptible to predation.…”

“…But, if a species is able to colonize and to gain reproductive success in habitats prior to the arrival of predators, would this species be more, or less vulnerable to predation than later colonizers? On the one hand, an early colonizer that is a poor competitor might also be less vulnerable to predation because of the tradeoff between competitive ability and predator vulnerability (Wissinger et al 1999, Kesavaraju et al 2008, Viola et al 2010). On the other hand, an early colonizer that occupies a habitat prior to colonization by predators may be both a poor competitor and predator vulnerable, as it has adapted to exploit environments with both low predation and low competition.…”

Nature of Predation Risk Cues in Container Systems: Mosquito Responses to Solid Residues from Predation

“…Such small aquatic habitats limit prey ability to avoid subhabitats where predation risk is high; hence, we expect prey in such habitats to respond to cues to predation risk by modifying behavior or life history. Although the presence of responses to predation risk cues are known in container systems (Juliano and Gravel 2002; Kesavaraju and Juliano 2004, 2008; Kesavaraju et al 2007a,b, 2008), the sources and type of those cues are poorly investigated.…”