Insect Parasites of the Virginia Pine Sawfly, Neodiprion pratti pratti

1963 ◽  
Vol 56 (5) ◽  
pp. 618-621 ◽  
Author(s):  
Marvin L. Bobb
Keyword(s):  
1964 ◽  
Vol 57 (3) ◽  
pp. 355-357
Author(s):  
George C. Becker ◽  
D. M. Benjamin

1958 ◽  
Vol 36 (2) ◽  
pp. 175-183 ◽  
Author(s):  
A. W. Ghent

The heads of feeding larvae of the jack pine sawfly are consistently oriented towards the needle tips. This orientation is not obtained from the apically-directed needle teeth, and is found to be independent of gravity and of the flexibility of the foliage. Though light can act to disrupt the orientation, larvae adopt the orientation in darkness so that light cannot be postulated as an essential directive stimulus. The behavior is identified as a "free-end" response, and possible underlying mechanisms are discussed.


Author(s):  
Phil Diamond

AbstractCompetition between a finite number of searching insect parasites is modelled by differential equations and birth-death processes. In the one species case of intraspecific competition, the deterministic equilibrium is globally stable and, for large populations, approximates the mean of the stationary distribution of the process. For two species, both inter- and intraspecific competition occurs and the deterministic equilibrium is globally stable. When the birth-death process is reversible, it is shown that the mean of the stationary distribution is approximated by the equilibrium. Confluent hypergeometric functions of two variables are important to the theory.


1992 ◽  
Vol 29 (1) ◽  
pp. 63 ◽  
Author(s):  
M. T. Davies ◽  
A. W. Davison ◽  
G. R. Port
Keyword(s):  

1968 ◽  
Vol 48 (2) ◽  
pp. 291-304
Author(s):  
SARAH A. CORBET

1. The first larval instar of Nemeritis lasts longer in young caterpillars of Ephestia than it does in older caterpillars. First-instar Nemeritis larvae in young hosts feed and grow very slowly, but they remain capable of fast growth if transferred to older host caterpillars. 2. Measurements of the protein concentration, the amino acid concentration and the freezing-point depression show rapid changes in the composition of the haemolymph of Ephestia caterpillars at that stage of larval development at which they first become capable of supporting the fast development of first-instar larvae of Nemeritis. 3. It is suggested that the rate of development of Nemeritis larvae depends on their rate of feeding, and that their rate of feeding is determined by a behavioural response to the composition of their food, the host's haemolymph; they feed slowly in young host caterpillars because the concentration of solutes (notably amino acids) in their food is so high. 4. A similar situation may hold when the development of insect parasites is delayed in diapausing hosts.


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