Involvement of Apolipohorin in Flight Muscle Histolysis
. Josefa Ceruto and Rush Oliver, Department of Biological and Physical Sciences, Benedict College.
The data from the half-sib experiment are used to address three principal questions: (1) Is JHE activity in the final nymphal stadium genetically correlated with fecundity and flight muscle histolysis? (2) From the relative values of the heritabilities and genetic correlations can we infer the probable contribution of JHE activity to the liability?
Flight Muscle Histolysis. - At final molt the principal flight muscles, the dorsal longitudinal muscles, are fully developed and typically massive in the macropterous morph, but small, undeveloped, or absent in the micropterous morph (Roff 1989; Mole and Zera 1994).
The heritabilities of the dichotomous traits, wing morph, and flight muscle histolysis (as shown later the five categories of histolysis can be collapsed into two without loss of information), were estimated using ANOVA as described in Mousseau and Roff (1989).
Fifty-nine percent of macropterous females had flight muscles showing no sign of histolysis, 21% showed partial muscle histolysis (categories 2, 3, 4), and 20% had no flight muscles remaining (full histolysis).
Mean fecundity of macropterous Gryllus firmus females categorized according to degree of histolysis of the dorsal longitudinal flight muscles.
firmus propensity of macropterous individuals to inititiate flight, rates of flight muscle histolysis, and the age schedule of fecundity change within morphs in lines selected for increased or decreased proportion macropterous in a manner consistent with the continuous model (Fairbairn and Roff 1990; Roff 1994b).
The significant correlations within wing morphs between fecundity ([F.sub.morph,f]) and [P.sub.mac,f] and between muscle histolysis ([H.sub.mac,f]) and [P.sub.mac,f] argue strongly for the continuous model and are inconsistent with the dichotomy model.
In these studies, the hemocytes appear to take an active role in the destruction of the basement membrane, cell sloughing, histolysis, or atrophy associated with pathogenic tissue remodeling.
Some evidence also suggests that certain defense-related proteins play a role in tissue histolysis during insect metamorphosis (Tryselius et al., 1992; Natori et al., 1999), and the onset of larval metamorphosis in an ascidian has been correlated with the differential expression of immune-related genes and the transepidermal migration of hemocytes into the larval tunic (Davidson and Swalla, 2002).