نتایج جستجو برای: larval measures
تعداد نتایج: 379387 فیلتر نتایج به سال:
while the «classical insecticides» (ddt: dieldrin, malathion, etc.) mainly affect the adult stage of insects, dimilin belongs to a new group of insecticidal compounds that kills the insect in its larval stages, but has no lethal affect on the adult insect. its empirical formula is c14h9h2~f2cl. diflubenzuron is proposed as common name for the trade name dimilin. studies were made on c. pipiens,...
Some marine invertebrate larvae expand the range of settlement cues to which they will respond as they age. How do relatively simple larvae achieve such complex changes in behaviour? Larvae of the Australian sea urchin Holopneustes purpurascens settle and metamorphose specifically in response to a settlement cue, dissolved histamine, produced by the host alga Delisea pulchra. Older H. purpurasc...
Conflict arises among social organisms when individuals differ in their inclusive-fitness interests. Ant societies are excellent models for understanding how genetic relatedness mediates conflict intensity. However, although conflicts within colonies typically arise over offspring production, the role of larvae as actors in social conflict has received little attention. We develop and empirical...
For marine organisms, decoupling between the planktonic larval stage and the benthic-associated juvenile stage can lead to variable patterns of population replenishment, which have the potential to inXuence the eVectiveness of marine reserves. We measured spatial and temporal variability in larval supply and recruitment of Wshes to coral reefs of diVerent protection levels and tested whether pr...
The interference of biological agents may cause behaviors such as interspecific predation, reducing their efficiencies. The interspecific predation of lacewing, Chrysoperla carnea (Steph.) and ladybeetle, Hippodamia variegata (Goeze) was investigated in the presence and absence of prey, Aphis gossypii Glover under laboratory conditions. In the presence and absence of prey, the larvae of lacew...
the population response of heliothis armigera larvae to nuclear polyhedrosis virus (npv) was investigated. the virus was introduced by permitting the larvae to feed on lettuce leaves. median lethal doses (ld50) were determined. the estimated ld50 values for the first, second, third, early, and late fourth larval instars were 5, 141, 1226, 5168 and 24553 polyhedra per larva respectively. in ...
Malaria vector control targeting the larval stages of mosquitoes was applied successfully against many species of Anopheles (Diptera: Culicidae) in malarious countries until the mid-20th Century. Since the introduction of DDT in the 1940s and the associated development of indoor residual spraying (IRS), which usually has a more powerful impact than larval control on vectorial capacity, the focu...
Background The Mantispidae are a distinctive group of Neuroptera known for the adults' possession of raptorial forelegs. There are four recognised, extant subfamilies of Mantispidae: the Mantispinae, Symphrasinae, Calomantispinae and Drepanicinae. The life history and larval behaviour of the subfamily Mantispinae is best known: the immatures are spider egg predators. Among the three remaining s...
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