Parasitoids physiology, development and behaviour | Boln. Asoc. esp. Ent. 21 (Supl.): 68-69 | 1997
Antennal functional áreas for sex recognition in some parasitoid hymenopterans
F. Bin, N. Isidoro, R. Romani & S.B. Vinson
ABSTRACT
A tentative defínition of functional áreas have been proposed for the male and female antennae of some taxa in relation to sex recognition. These áreas are composed of sensilla, glands and mecnanical structures. fcTouch and Taste ?_reas1´ (TTA) include only Uniporous Gustatory Sensilla (UGS), ´´Reléase and Spread ?_reas´´ (RSA) are composed of glands belonging to either class 1 or 3 , mechanosensilla of one or two types and usually conspicuous cuticular structures which spread the secretion mechanically.
Depending on taxa, various combinations are possible based on the presence of glands in one sex or both. Exatnples are provided for several species correlating morphological (SEM and TEM) and behavioral observations.
Male glands are present on different antennomeres, e.g. Diapriidae: antennomere 1 (scape) is modified by a deep indentation (Platymischus dilatatus), antennomere 3 has a tyloid and 4 a peg (Coplera occidentali$e 4 has only a pointed tyloid (Trichopfia ? drosophilae). In this last species female receptivity can be prevented by covering the male tyolid with glue, i.e. sealing the gland openings.
Female glands have been observed on the dorsal side of several antennomeres in Neodryinus íyphlocybae and other dryinids. Because of their location they are presumed to be involved in communication between sexes.
Both sexes in Scelionidae and Platygastridae have antennomeres with glands in different combinations. Both have dorsal glands but only males have a ventral or a lateral one. In Trissolcus basalis ablation of some male antennomeres or the peg, a reléase and spread structure, makes sex recognition impossible.
These and other examples show the diversity of reléase structures associated with glands. Therefore a glandular formula, based on sex / antennomeres involved / gland type / type and location of reléase and spread structure, is proposed. Instead, the female TTA appears to be quite uniform probably composed of only UGS located latero-ventrally in one or both sexes.
There are new aspects, as regards the final step of sex selection strategy due to the intra-antennal communication during sex recognition since one or both sexes produce a recognition and/or an aphrodisiac pheromone. Therefore the antennae of one or both sexes also work as signa! emitters and not only as receivers. However, these and other aspects need further investigation to define the function of two different glands in the males, the composition of secretions, their role in reproductive isolation and finally the different sex recognition mechanisms in parasitoids devoid of antennal glands.
