Journal of Chemical Ecology, Vol. 8, No. 2, 1982
MANDIBULAR GLANDS OF MALE Centris adani, (HYMENOPTERA: ANTHOPHORIDAE) Their Morphology, Chemical Constituents, and Function in Scent Marking and Territorial Behavior 1
S.B. V I N S O N , 2 H . J . W I L L I A M S , 2 G . W . F R A N K I E , 3 J . W . W H E E L E R , M.S. BLUM, 5 and R.E. COVILLE 3
4
ZDepartment of Entomology, Texas A&M University College Station, Texas 77843 3Department of Entomological Sciences, University of California Berkeley, California 94720 4Department of Chemistry, Howard University Washington, D.C. 20059 5Department of Entomology, University of Georgia Athens, Georgia 30602 (Received December 9, 1981; revised June 16, 1981) Abstract--Males of the solitary Central American bee Centris adani Cockerell possess enlarged mandibular glands filled with a fragrant fluid that was shown by gas chromatographic and mass spectral analysis to consist of nerol, geraniol, neral, ethyl laurate, and geranyl acetate. Male bees set up territories by marking a semicircular array of grass stems with these compounds. Grass stems marked by the bees showed the presence of the same chemicals. Key Words--Centris adani, mandibular gland, geraniol, nerol, neral, geranyl acetate, ethyl laurate, territoriality, phe~ ~rr )he, solitary bee.
INTRODUCTION Males of some Hymenoptera species are known to establish and maintain territories against conspecific males for the suspected purpose of attracting and mating with conspecific females. In the case of territorial bees, most ~Approved as TA 16466 by the Director, Texas Agricultural Experiment Station. All programs and information of the Texas Agricultural Experiment Station are available without regard to race, ethnic origin, religion, sex or age. Supported in part bY NSF grant DEB 7063936 and the National Geographic Society. 319 0098-0331/82/0200-0319503.00/0 9 1982 Plenum Publishing Corporation
320
VINSON ET AL.
defended areas cover a few square meters and are often associated with either nesting sites (Cruden, 1966; Alcock et al., 1978) or with food plants (Haas, 1960; Crazier and Linsley, 1963; Jaycox, 1967). Males of several Centris species have been reported to defend territories (Frankie and Baker, 1974; Alcock, 1976), and in some cases the presence of an odor emanating from the males has been noted (Raw, 1975; Frankie et al., 1980). In this regard, males of some Centris species resemble males of Bombus and Psithyrus bee species and some Philanthine and Nyssonine wasp species that mark their territorial sites with cephalic secretions (Kullenberg, 1956; Free and Butler, 1959; Calam, 1969; Borg-Karlson and Teng6, 1980). Frankie et al. (1980) reported that male Centris adani Cockerelt, observed in Costa Rican dry forests, were territorial in certain grassy habitats not necessarily associated with nest sites or food plants. Territories were also observed in the crowns of some flowering host trees. These territories appeared to be maintained by compounds that the bees deposited on surrounding vegetation. In this paper we identify the mandibular glands as the source of these chemicals, describe the morphology of these glands, and analyze the compounds extracted from them. We also describe how these chemicals are deposited on vegetation by the bees. M E T H O D S AND MATERIALS
The study site at which collections were made was located in the Pacific lowland dry forest (
MANDIBULAR GLANDS OF MALE Centris adani, (HYMENOPTERA: ANTHOPHORIDAE) Their Morphology, Chemical Constituents, and Function in Scent Marking and Territorial Behavior 1
S.B. V I N S O N , 2 H . J . W I L L I A M S , 2 G . W . F R A N K I E , 3 J . W . W H E E L E R , M.S. BLUM, 5 and R.E. COVILLE 3
4
ZDepartment of Entomology, Texas A&M University College Station, Texas 77843 3Department of Entomological Sciences, University of California Berkeley, California 94720 4Department of Chemistry, Howard University Washington, D.C. 20059 5Department of Entomology, University of Georgia Athens, Georgia 30602 (Received December 9, 1981; revised June 16, 1981) Abstract--Males of the solitary Central American bee Centris adani Cockerell possess enlarged mandibular glands filled with a fragrant fluid that was shown by gas chromatographic and mass spectral analysis to consist of nerol, geraniol, neral, ethyl laurate, and geranyl acetate. Male bees set up territories by marking a semicircular array of grass stems with these compounds. Grass stems marked by the bees showed the presence of the same chemicals. Key Words--Centris adani, mandibular gland, geraniol, nerol, neral, geranyl acetate, ethyl laurate, territoriality, phe~ ~rr )he, solitary bee.
INTRODUCTION Males of some Hymenoptera species are known to establish and maintain territories against conspecific males for the suspected purpose of attracting and mating with conspecific females. In the case of territorial bees, most ~Approved as TA 16466 by the Director, Texas Agricultural Experiment Station. All programs and information of the Texas Agricultural Experiment Station are available without regard to race, ethnic origin, religion, sex or age. Supported in part bY NSF grant DEB 7063936 and the National Geographic Society. 319 0098-0331/82/0200-0319503.00/0 9 1982 Plenum Publishing Corporation
320
VINSON ET AL.
defended areas cover a few square meters and are often associated with either nesting sites (Cruden, 1966; Alcock et al., 1978) or with food plants (Haas, 1960; Crazier and Linsley, 1963; Jaycox, 1967). Males of several Centris species have been reported to defend territories (Frankie and Baker, 1974; Alcock, 1976), and in some cases the presence of an odor emanating from the males has been noted (Raw, 1975; Frankie et al., 1980). In this regard, males of some Centris species resemble males of Bombus and Psithyrus bee species and some Philanthine and Nyssonine wasp species that mark their territorial sites with cephalic secretions (Kullenberg, 1956; Free and Butler, 1959; Calam, 1969; Borg-Karlson and Teng6, 1980). Frankie et al. (1980) reported that male Centris adani Cockerelt, observed in Costa Rican dry forests, were territorial in certain grassy habitats not necessarily associated with nest sites or food plants. Territories were also observed in the crowns of some flowering host trees. These territories appeared to be maintained by compounds that the bees deposited on surrounding vegetation. In this paper we identify the mandibular glands as the source of these chemicals, describe the morphology of these glands, and analyze the compounds extracted from them. We also describe how these chemicals are deposited on vegetation by the bees. M E T H O D S AND MATERIALS
The study site at which collections were made was located in the Pacific lowland dry forest (
