The locomotory activity of Zonocerus variegatus (L.) (Orthoptera: Acrididae) under natural light,temperature, and humidity conditions

Summary

The locomotory activity of adult Zonocerus variegatus (L.) was investigated in an insectary, using an aktograph apparatus. Under natural light, temperature, and humidity conditions, male and female adults were markedly active during the daytime but showed very little activity during the early hours of the night. The males were found to be more active than the females. Individuals of the same sex showed slightly different patterns of activity. There was some correlation between increased activity and a period of bright sunshine accompanied by increased temperature. Starvation for 24 hours before and for 48 hours during experiments affected the normal locomotory activity of the grasshopper.     

Individual and geographical variation in the stridulatory file of Omocestus viridulus (L.) (Orthoptera: Acrididae)

Summary

Samples of male specimens of Omocestus viridulus from 14 European countries were used to study the individual and geographical variation in the characters associated with the stridulatory file. Significant overall variation between the samples was demonstrated for the length of file, average density of pegs, length of hind femur and ratio of file length to hind femur length.

This variation was found to be significantly correlated with several environmental factors, particularly annual range of temperature and amount of precipitation. These factors were considered to be good indicators of continentality, specimens from more continental regions having longer hind femora and longer files with a lower density of pegs. File length was found to be inversely correlated with amount of precipitation even when considered as a proportion of the hind femur. Number of pegs was also found to be inversely correlated with precipitation. In showing that femur length and file length increase and density decreases with continentality, the results agree with those of my previous study (Pitkin, 1976), in which British samples were found to have shorter femora and shorter files with a greater density of pegs than German samples.

The present study, while establishing that the stridulatory file varies geographically, does not deny its usefulness as a taxonomic tool, particularly when it is used in combination with other characters. When stridulatory characters are used on their own, individual and geographical variability within the species must clearly be taken into account.     

British species of the parasitic cynipid-wasp genus Aegilips (Hymenoptera: Cynipoidea,Anacharitinae)

The British species of Aegilips are revised and a key to species is provided. Of the eight species previously described from Britain seven are synonymized under the name A. nitidula (Dalman). Three new species (A. atricornis, A. romseyensis and A. vena) are described. A neotype is designated for A. nitidula (Dalman) and lectotypes are designated for A. rufipes (Westwood), A fumipennis (Westwood) and A. dalmani Reinhard.     

Notes on distinguishing the cocoons and the juveniles of Hirudo medicinalis and Haemopis sanguisuga (Hirudinea)

Difficulties encountered previously in separating the cocoons and some juveniles of Hirudo medicinalis and Haemopis sanguisuga have been resolved by the present study. The cocoons of Hirudo medicinalis are larger and have a different structure from those of Haemopis sanguisuga. Some of the darker juveniles of Haemopis sanguisuga may be confused with those of Hirudo medicinalis, but can be separated by careful examination of both dorsal and ventral colour patterns.