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K.V. Makarov, E.E. Bokhovko
Continuity of chaetom pattern in Brachinus-larvae developing with hypermetamophosis (Coleoptera: Carabidae)
Russian Entomol. J., 2005, 14(4): 263-274
(RUSSIAN ENTOMOLOGICAL JOURNAL, 2005)
KEYWORDS:
larvae, chaetotaxy, morphology, adaptations, Coleoptera, Carabidae, Brachinini.
ABSTRACT.
Extrenal morphology and the chaetoítaxy of all larval stages of carabid
beetle Brachinus elegans Chaudoir, 1842 were studied. First larva of this
beetle is triangulina-like, whereas larvae II and III are engorged, scarcely
moving forms. In spite of hypermeítamorphosis, the great continuity of
chaetome compoísition was revealed. The analysis of the topology of chaetome
elements during larval development allowed to ascertain follows:
1) the strong modification of the cephalic capsule is caused but the
disproportional enílargement of basal regions of frontal and parietal
scleriítes; 2) body tergits increase in size proportionally;
3) pleurites and ventrites become hypertrophied; 4) the reduction and
immobilization of leg segments have not effect on the set of their chetome
elements. There are two the most important tendencies in chaetome formaítion
in Brachinus larvae during the ontogenesis: the weakening of sensorial and
locomotory elements and the development of the supporting chaetome of
abdoíminal ventrites and pleurites. The assessment of the transformation of
different adaptive and nonadaptive structures enabled to select the
taxonomically valuable features. Their application supports the hypothesis
of the proximity of Brachinini to the group Truncatipenne within
Limbataconchifera.