Manual for Diagnosis of Screw-worm Fly - xcs consulting

Hydrocarbon content (Table 1)
Chrysomya bezziana
The cuticular hydrocarbons of newly emerged C. bezziana comprise mainly saturates with
carbon chain lengths of ca 25 to 37. The largest components are 2-methyloctacosane (ECL=
28.64); internal-methylnonacosane (i-methylnonacosane, 29.33); 2-methyltriacontane (30.64);
i-methylhentriacontane (31.31); and i-methyl- and dimethyl-tritricontane (33.31 and 33.57).
Males and females have identical profiles. Between emergence and day 5, quantitative
changes in cuticular hydrocarbon composition occur; these are more pronounced for females
than males. From day 5 the profiles stabilise again. The percentages of several components,
mainly those with carbon chain lengths greater than 34, increase while those of other
components decrease. Values for major components are given in the Table for newlyemerged
and 5 day old flies. Flies of intermediate ages have hydrocarbon compositions
between those of these two stages.
Chrysomya megacephala
Young C. megacephala flies also contain hydrocarbons which are predominantly alkanes,
but mainly of shorter chain lengths than those of C. bezziana. The two largest components
are i-methylheptacosane (27.33) and 2-methyloctacosane (28.64). Other major components
include n-heptacosane (27.00), n-nonacosane (29.00) and i-methylnonacosane (29.33). The
most abundant alkanes are heptacosene and nonacosene (26.79 and 28.81, 2-3%). Cuticular
hydrocarbon data for older flies are not available.
Chrysomya saffranea
C. saffranea contains hydrocarbons very similar to those of C. megacephala. The mean
value of heptacosene (26.79) in females is higher, but this component is very variable and
some individuals have levels comparable with those of C. megacephala. Again cuticular
hydrocarbon data for older flies are not available.
Cochliomyia hominivorax
Agriculture, Fisheries and Forestry - Australia
The cuticular hydrocarbons of newly-emerged male and female Co. hominivorax are
dominated by those with a C29 carbon chain, particularly i-methylnonacosane (29.33).
2-methyloctacosane (28.64) is also abundant but all other components are quite minor.
The hydrocarbon composition of this species changes much more with age and sex than
does that of C. bezziana (see Pomonis 1989). By day 5, males have aquired large quantities
of n- and i-methylpentacosane and heptacosane and have lost most of the i-methyl- and
3-methylnonacosane. Females also acquire n- and i-methylheptacosane (but not
pentacosane) as well as increasing the proportions of longer chain length material (greater
than C30).
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