Two of the most important behaviors of any organism are feeding and mating. The fly Phormia regina is one of the best systems for investigating feeding behavior. We know more about various stimuli initiating feeding, the chemoreceptors included in detecting these stimuli, and the feedback systems involved in controlling cessation of feeding in this fly than any other animal system. Thus, the various types of inputs and outputs involved in feeding on carbohydrates have been well documented. Carbohydrates are essential for the maintenance of life and are used as fuels for different types of locomotion. Carbohydrates, however, as a single food item do not lead to sexual behavior or egg development in this fly. The important dietary item essential for the development of sexual behavior in both sexes is protein. Without it, sexual behavior does not occur. Mating behavior is essential for any bisexual animal species to exist. We are just beginning to understand those factors involved in both the ontogeny of sexual behavior and its regulation once the animal is sexually mature. My laboratory is concentrating on how diet influences mating behavior. How dietary proteins and hormones influence the ontogeny of sexual behavior and regulate its expression once the adults are sexually mature is the main focus of my laboratory.

John G. Stoffolano, Jr.

Effect of Diet and Hormones on
Sexual Behavior in Insects

Many aspects of insect sexual behavior are under neuroendocrine control. Two hormone families, the ecdysteroids and juvenile hormones, are present in adult insects. Their involvement in regulating mating behavior and its ontogeny needs to be clarified. In addition, numerous neuropeptides and peptide hormones may also be involved. The advantage of using Phormia regina as our choice of study is that mating behavior can be turned on and off by regulating the adults' diet. Any behavior that can be regulated so easily is much easier to study than behaviors involving gradual changes.

My major current research goal is to determine the hormone titers following a protein meal and to correlate these with the onset of mating behavior. At the same time, we are interested in knowing what it is in the proteinaceous diet that serves as the trigger to activate the neuroendocrine system involved in regulating mating behavior. Using this information, we then plan to manipulate the system, either by gland removal or exogenous application of the appropriate hormones. We believe that the important internal messengers that interface between diet and the overt expression of mating behavior are the biogenic amines. Using HPLC, immunocytochemistry, and GC-MS, we will determine which biogenic amine(s) are involved in mating behavior. Currently we are also investigating myoinhibitory and stimulatory peptides on crop filling, emptying and feeding behavior. My long-term research objective is to put together the pieces of the puzzle that will give us a clear picture of how nutrition and various internal chemical messengers, such as hormones, neuropeptides, peptide hormones, and biogenic amines, interact to produce mating behavior.

Representative Publications:

Stoffolano, J.G., Jr., E.N. Tobin, J. Wilson and C.-M. Yin. (1995). Diet affects insemination and sexual activity in male Phormia regina (Diptera: Calliphoridae). Ann. Entomol. Soc. Amer. 88: 240-246.

Stoffolano, J.G., Jr., H. Duan and C.-M. Yin. (1995). Crop and midgut filling and emptying in female Phormia regina (Diptera: Calliphoridae) fed on a liver diet. J. Med. Entomol. 32: 190-194.

Yin, C.-M., B.-X. Zou, M. Jiang, M.-F. Li, W. Qin, T.L. Potter and J.G. Stoffolano, Jr. (1995). Identification of juvenile hormone III bisepoxide (JHB3), juvenile hormone III and methyl farnesoate secreted by the corpus allatum of Phormia regina (Meigen), in vitro and function of JHB3 either applied alone or as a part of a juvenoid blend. J. Insect Physiol. 41: 473-479.

Qin, W.-H., C.-M. Yin and J.G. Stoffolano, Jr. (1995). The role of the corpus allatum in the control of vitellogenesis and fat body hypertrophy in Phormia regina (Meigen). J. Insect Physiol. 41: 617-626.

Liscia, A., J.G. Stoffolano, Jr., I. Tomassini Barbarossa, P. Muroni, and R. Crnjar. (1995). Sensitivity to albumin and its terminal amino acids of labellar taste chemoreceptors in Protophormia terraenovae (Diptera: Calliphoridae). J. Insect Physiol. 41: 597-602.

Liscia, A., J.G. Stoffolano, Jr., I. Tomassini Barbarossa, P. Muroni and R. Crnjar. (1995). Effects of ATP on the interaction of albumin and its C-terminal amino acid L-alanine with the "sugar" receptor cell in Protophormia terraenovae (Diptera: Calliphoridae). J. Insect Physiol. 41: 717-721.

Stoffolano, J.G., Jr., M.-F. Li, J.A. Sutton and C.-M. Yin. (1995). Faeces feeding by adult Phormia regina (Diptera: Calliphoridae): impact on reproduction. Med. and Vet. Entomol. 9: 388-392.

Yin, C.-M. and J.G. Stoffolano, Jr. (1997). Juvenile hormone regulation of reproduction in the cyclorrhaphous Diptera with emphasis on oogenesis. Arch. of Insect Biochem. and Physiol. 35: 513-537.

Qin, W.-H., C.-M. Yin and J.G. Stoffolano, Jr. (1997). Control of pupal fat body disappearance in the female black blow fly, Phormia regina (Meigen), by the brain and the corpus allatum. J. Insect Physiol. 43: 533-540.

Evans, B.P., J.G. Stoffolano, Jr., C.-M. Yin and J.S. Meyer. (1997). A pharmacological and endocrinological study of female insemination in Phormia regina (Diptera: Calliphoridae). J. Insect Behavior. 10: 493-508.

Stoffolano, J.G., Jr., E. Schauber, C.-M. Yin, J.A. Tillman and G.J. Blomquist. (1997). Cuticular hydrocarbons and their role in copulatory behavior in Phormia regina (Meigen). J. Insect Physiol. 43: 1065-1076.

Stoffolano, J.G., Jr. and J. Majer. (1997). Comparison between tsetse fly synthetic diet and bovine blood on reproduction and survivorship in Tabanus nigrovittatus (Diptera: Tabanidae). J. Med. Entomol. 34: 738-740.

Yin. C.-M., B.-X. Zou, M.-F. Li and J.G. Stoffolano, Jr. (1997). Using the pungent seed flesh of the durian fruit, Durio zibethinus, to synchronize the second ovarian cycle in Phormia regina (Diptera: Calliphoridae). Zoological Studies. 36: 353-359.

Evans, B.P., J.G. Stoffolano, Jr., C.-M. Yin and J.S. Meyer. (1998). The effects of injection of amphetamine on female insemination in the black blow fly, Phormia regina (Diptera: Calliphoridae). Physiol. Entomol. 23: 20-24.

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