We investigated the effects of the predatory backswimmer, Anisops sardea, on oviposition habitat selection of mosquitoes and other dipterans, and on community structure in experimental pools. We predicted that those dipteran species whose larvae were shown to be highly vulnerable to predation by Anisops would avoid Anisops pools when choosing an oviposition site. We established the following treatments in plastic tubs: (1) Control (without Anisops); (2) Free Anisops (ten Anisops within pool but not caged); (3) Caged Anisops (ten Anisops in cage). The pools were open to colonization by insects. We added resting stages of crustaceans and first instar larvae of the mosquitoes Culiseta longiareolata and Culex laticinctus. Among the dipteran species, Culiseta longiareolata, Culex laticinctus, Chironomus riparius (Chironomidae) and Forcipomyia sp. (Ceratopogonidae), only Culiseta larvae were highly vulnerable to predation. As predicted, based on larval vulnerability, Culiseta, but not the other species, avoided Anisops pools when ovipositing. Free Anisops reduced taxon richness. This reduction resulted largely from the elimination of the cladoceran Ceriodaphnia sp. and Culiseta in most free Anisops pools. Thus, Anisops sardea structures the community, both by a behavioral response of prey to its presence and by consumption of prey.
Bibliographical noteFunding Information:
We thank Moshe Kiflawi and Joel E. Cohen for valuable discussion and Moshe Kiflawi for field assistance. We also thank Tamar Krugman and Eden Orion for logistical help, Yehuda Braverman and John Martin for taxonomic help, and two anonymous reviewers whose comments lead to an improved manuscript. The study was supported by US–Israel Binational Science Foundation grant 98-390, awarded to L. Blaustein and M. Mangel.
- Culiseta longiareolata
- Oviposition habitat selection
- Risk of predation
- Species richness
- Temporary pools
ASJC Scopus subject areas
- Aquatic Science