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Effects of isolation and crowding on the haemolymph pigment composition of the desert locust, Schistocerca gregaria (Orth., Acrididae)
Author(s) -
Deng A. L.
Publication year - 2002
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1046/j.1439-0418.2002.00646.x
Subject(s) - schistocerca , desert locust , locust , hemolymph , acrididae , biology , absorbance , nymph , orthoptera , pigment , insect , zoology , botany , chemistry , chromatography , organic chemistry
An experimental study on the effect of isolation and crowding of the desert locust, Schistocerca gregaria (Forskål) on haemolymph pigment composition (as measured by absorbance ratios at 460 and 680 nm) was carried out at the International Centre of Insect Physiology and Ecology, Nairobi. The results showed that haemolymph absorbance ratios of gregarious and solitarious locusts were different (P < 0.05) and that there was no phase‐specific sex differentiation with regard to this measure (P < 0.05). The haemolymph pigment composition changes during isolation and grouping showed contrasting trends. It changed rapidly in nymphs, but slowly and erratically in adults both resulting from isolation and grouping at hopper stage. Significant shifts in locust phase status were recorded in both situations in nymphs in F 0 generation, and in the adults by the end of the F 2 and F 3 generations of solitary and gregarious conditions, respectively. Shifting of fledglings did not induce significant changes in their mean absorbance ratios in both situations, i.e. isolation and crowding within F 0 generation. The ratio of length of posterior femur (F) to greatest width of the head capsule (C) changed either at a similar rate or more often slower than the haemolymph pigment ratio and both required more than a generation to transform fully. The study has shown that haemolymph pigment composition could be a suitable measure for monitoring phase changes at nymphal stages of the desert locust.