Ll. Fry et al., FIELD INTRODUCTIONS AND ESTABLISHMENT OF THE TADPOLE SHRIMP, TRIOPS-LONGICAUDATUS (NOTOSTRACA, TRIOPSIDAE), A BIOLOGICAL-CONTROL AGENT OF MOSQUITOS, Biological control, 4(2), 1994, pp. 113-124
The tadpole shrimp (Triops longicaudatus LeConte) is a potential biolo
gical control agent for some species of mosquitoes developing in tempo
rary aquatic habitats. It is an effective larval predator that also ac
tively deters mosquito oviposition. Its use in practical control progr
ams depends in part on its ability to establish permanent populations
where it is introduced. Introductions of its desiccation-resistant egg
s (both lab-reared and field-collected) as well as gravid adults were
made in 16 ponds in southern California. Tadpole shrimp density was mo
nitored over five floodings from Fall 1991 through Summer 1992. The ta
dpole shrimp was able to colonize and persist in 94% of the ponds. All
methods of introducing T. longicaudatus were successful, but its hard
y egg is the preferred stage for field distribution. The hatching rate
for lab-reared shrimp eggs in the ponds ranged from 13.7 to 19.4% (XB
AR = 15.9%, N = 1135-2353/pond). In a following experiment, a high den
sity of tadpole shrimp was shown to have a significant negative impact
on mosquito larvae (Culicidae) (P < 0.05), and on nontarget midge lar
vae (Chironomidae) (P < 0.05), but not on two other abundant insects-m
ayflies (Baetidae) or brine flies (Ephydridae). (C) 1994 Academic Pres
s, Inc.