The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta . I. Sexual dimorphism in the distribution of antennal sense organs in five species

Sexual dimorphism in the distribution of antennal sense organs is common among adults of the genus Periplaneta. In three out of the four strains of Periplaneta americana examined, adult males had more contact chemoreceptors than females. In the fourth strain of P. americana and in P. australasiae, P. brunnea, P. fuliginosa , and P. japonica , no statistically supportable sexual dimorphism of contact chemoreceptors was found. However, in all strains and species of Periplaneta examined, sexual dimorphism was found in the total number and/or density of olfactory sensilla. Male adults had nearly twice as many olfactory sensilla as female adults. These observations are consistent with the behavioral observation that males within the genus Periplaneta rely on the reception of an airborne pheromone for the initiation of courtship behavior. In P. americana , where sexual dimorphism was found in the contact chemoreceptors, contact stimuli release the full wing raising display and presentation in males during courtship.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50261/1/1051490202_ftp.pd

Juvenile hormone inhibits differentiation of olfactory sense organs during postembryonic development of cockroaches

The density of olfactory sense organs on the antenna of the cockroach, Leucophaea maderae, is relatively constant throughout larval development (average 400 sensilla/mm2), but undergoes a substantial increase at the adult state (to about 620 sensilla/mm2). Experimental manipulations of juvenile hormone (JH) activity result in either supernumerary larval instars (induced by unilaterla antennectomy or addition of exogenous JH), or premature adulthood (induced by allatectomy). The density of antennal sensilla remains at the larval level during the extra instars, but increases to the adult level or surpasses it at the terminal ecdysis following the induction of extra instars. Adultoids resulting from allatectomized sixth instars also have the high density of antennal olfactory sensilla characteristic of the normal adult. These data suggest that an interplay of surface area effects and an inhibitory action of JH controls the pattern of postembryonic development of antennal olfactory sensilla. Limited behavioural observations of the insects resulting from these experiments are consistent with the hypothesis that sex attractant-specific olfactory receptors appear only at the adult stage. However, electrophysiological data will be needed to confirm or negate this hypothesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22347/1/0000793.pd

The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta . III. Normal intra- and interspecific behavioral responses and responses of insects with juvenile hormone-altered antennae

Male cockroaches of the species Periplaneta americana rely on a female-produced airborne pheromone to initiate courting behavior. The male responds to the presence of the pheromone with rapid, oriented locomotion. Contact with the female (or other males or larvae) elicits wing-raising and other responses characteristic of male courtship behavior. Males of other species within the genus Periplaneta also respond to a female-produced pheromone, but with less intensity than P. americana. Cross-species testing shows that P. brunnea males respond to the Periplaneta pheromone with the same intensity elicited by the P. brunnea pheromone. A second reaction group containing P. australasiae, P. fuliginosa , and P. japonica also responds to the P. americana pheromone and their conspecific pheromones, but with a low intensity characteristic of these species. Alteration of the antennal morphology of P. americana males can be experimentally induced by manipulating the level of juvenile hormone during development. Males with a full adult complement of olfactory receptors all respond behaviorally to the pheromone. Adult males with larval antennae produced by bilateral treatment with exogenous juvenile hormone-mimic do not respond to the pheromone, although they are completely adult in other respects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38080/1/1401990109_ftp.pd

[Letter from Rollie Schafer to Vicki Rosenberg, January 2, 1990]

Photocopy of a letter from Rollie Schafer to Vicki Rosenberg certifying a $5,000 cash contribution to the funds matching requirement included in the Getty Center for Education of the Arts grant. It is allotted for the cost of graduate research assistants

The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta . II. Juvenile hormone regulates sexual dimorphism in the distribution of antennal olfactory receptors

Sexual dimorphism of antennal sense organs appears only at the adult stage during normal development of the cockroach, Periplaneta americana. Adult males acquire approximately twice as many olfactory sensilla as females at the terminal ecdysis. When terminal instar larvae are subjected to unilateral antennectomy, most ecdyse to supernumerary larvae rather than adults. Sexual dimorphism is not evident in the intact (unamputated) antenna during the extra larval stage, but appears at the following ecdysis which leads to the adult stage. Allatectomy of male and female larvae in the penultimate instar produces adultoids which show antennal sexual dimorphism. Whole-body treatment of terminal instar larvae with exogenous juvenile hormone-mimic (JH-M) results in supernmerary larvae which lack antennal sexual dimorphism. When these superlarvae are removed from the influence of JH-M, they ecdyse to adults with antennal sexual dimorphism. Topical application of JH-M to male antennae early in the terminal larval instar results in the emergence of adults which lack the total male complement of antennal sensilla, but are otherwise normal-appearing. These results indicate that an inhibitory action of juvenile hormone prevents the appearance of antennal sexual dimorphism during normal larval development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38077/1/1401980305_ftp.pd