William G. Eberhard

Universidad de Costa Rica

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R. D. Briceño

Universidad de Costa Rica

Gilbert Barrantes

Universidad de Costa Rica

Bernhard A. Huber

Zoological Research Museum Alexander Koenig

Rafael L. Rodrı́guez

University of Wisconsin–Milwaukee

Costa Rica

Migration Institute of Australia

Anita Aisenberg

Instituto de Investigaciones Biológicas Clemente Estable

Rosannette Quesada

Universidad de Costa Rica

William T. Wcislo

Smithsonian Tropical Research Institute

Jaime R. Ticay-Rivas

Universidad de Las Palmas de Gran Canaria

Carlos Cordero

Universidad Nacional Autónoma de México

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Universidad de Costa Rica

Smithsonian Tropical Research Institute

Universidad Nacional Autónoma de México

Smithsonian Institution

Universidade de São Paulo

American Museum of Natural History

Cornell University

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Centre National de la Recherche Scientifique

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Apparent Stimulatory Function of Species-specific Male Genitalic Setae in Aelurus septentrionalis (Hymenoptera: Tiphiidae)

Journal of the Kansas Entomological Society (2004)

William G. Eberhard

Howard Evans was the first to study the details of how male and female genitalia lock together during phoretic copulation in tiphiid and bethylid wasps (Evans, 1969). He found striking differences in the mechanisms that hold males and females together, confirming that phoretic copulation has evolved several times independently in these wasps. The tiphiid subfamily Thynninae, in which phoretic copulation occurs, is widely distributed in Australia and South America. Aelurus is the genus with the northernmost distribution (Kimsey, 1996), and its northenmost representative, A. septentrionalis Kimsey, is known from Panama and Costa Rica (Kimsey, 1991). Very little is known about the biology of Aelurus. Judging by the hosts of related species, they are probably parasites of scarab or other soil-dwelling beetle larvae (Evans, 1969; Kimsey, 1996 and pers. comm.). The male carries the female in flight, but releases her readily when captured; males of A. septentrionalis have been collected at lights at night (Kimsey, 1991). On the sunny morning of 15 June, 2002, during the second month of the wet season, I saw several male A. septentrionalis flying and walking on vegetation at the edge of an overgrown coffee field near San Antonio de Escazu, San Jose Province, Costa Rica (el. approx. 1400 m). Both solitary males and males carrying females were apparently feeding on the upper surfaces of leaves on a low-hanging branch of a tree, perhaps on honeydew. The females dangled apparently immobile, and did not appear to feed. In more than 20 years of entomological observations in this area, I have never seen this conspicuous species on any other occasion. I sprayed three pairs with a freezing spray (ethyl chloride), and succeeded in obtaining one coupled pair, which was immediately fixed in ethyl alcohol and subsequently prepared with standard procedures for examination with a scanning electron microscope. A voucher specimen has been placed in the entomology collection at the University of California at Davis.

Panama

Honeydew

10.2317/0022-8567(2004)077[0837:asfosm]2.0.co;2

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Copulatory courtship and genital mechanics of three species ofMacrodactylus(Coleoptera Scarabaeidae Melolonthinae)

Ethology Ecology & Evolution (1993)

William G. Eberhard

Abstract Female Macrodactylus costulatus, sericinus, and sylphis mated repeatedly while feeding on flowers and fruits as they matured eggs. Courtship in all species occurred both prior to and following intromission, with most courtship being performed after the male had achieved intromission. Females often prevented males from mounting, and often prevented mounted males from achieving intromission. They also probably often prevented male genitalia from penetrating past the vulva, even after they had allowed them into the genital chamber. Males at least sometimes pushed forcefully at structures both on the surface of the female and within her reproductive tract. Copulation probably involved a combination of force and persuasion. It often failed to result in complete transfer of sperm. Males displayed striking virtuosity in both the morphology and behavior of their genitalia, which assumed at least four different morphological configurations. At least five and perhaps up to eight different functions were performed by male genitalia. Small sacs near the tips of the male parameres were probably used by males as "foot-in-the-door" devices to gain access to the female's genital chamber, while the spiney collar and tongue may have helped open the vulva to allow deeper penetration. The energetic and persistent courtship which occurred after intromission was achieved may lunction at least partly to induce the female to allow the male to reach the deeper stage of penetration necessary for spermatophore formation, and perhaps to permit transfer of sperm to her spermathecal duct. Male courtship behavior included movements of his head, vibration and sweeping movements of his middle legs, rubbing with his abdominal bristles against the female's elytra, strong substrate vibrations of unknown origin in the male's body, and tapping and stroking with his genitalia on the external surface of the female's abdomen while he held her with his specialized front legs. Pairings in the field lasted up to several days, but there was no sign of size biases in either paired males or females. Males were more susceptible to predation by a common predator than were females when beetles were paired. Keywords: copulatory courtshipcryptic female choicesexual selectiongenitalic evolutionspecies-specific characters

Spermatophore

Courtship display

10.1080/08927014.1993.9523113

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Copulation behavior inside and outside the beetleMacrohaltica jamaicensis (Coleoptera, Chrysomelidae)

Journal of Ethology (1996)

William G. Eberhard Sarah Kariko

Animal ecology

Spermatophore

Courtship display

Female sperm storage

10.1007/bf02350093

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Citations (26)

Fitting together: copulatory linking in some Neotropical Chrysomeloidea

DOAJ (DOAJ: Directory of Open Access Journals) (2006)

R. Wills Flowers William G. Eberhard

Source

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7.2 Frequent Rapid, Divergent Evolution of Genitalia

Princeton University Press eBooks (1996)

William G. Eberhard

10.1515/9780691207209-066

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9.3 Lack of Intraspecific Genetic Differences

Princeton University Press eBooks (1996)

William G. Eberhard

10.1515/9780691207209-077

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6.7 Taking Stock

Princeton University Press eBooks (1996)

William G. Eberhard

10.1515/9780691207209-062

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7.1 Female Reproductive Ducts: A Tortuous Route to the Egg

Princeton University Press eBooks (1996)

William G. Eberhard

10.1515/9780691207209-065

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10.2 Consequences for Sexual Selection Theory

Princeton University Press eBooks (1996)

William G. Eberhard

10.1515/9780691207209-082

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Chapter 4. Putting pieces together

University of Chicago Press eBooks (2020)

William G. Eberhard

Abstract The list of functions that webs perform in prey capture is long and varied: intercept prey; absorb their momentum and stop them; adhere to them and retain them until the spider arrives to attack; maintain the web's physical integrity in the face of environmental perturbations such as wind; break, when the web is unable to stop an object, with a minimum of damage to the rest of the web; transmit vibrations from the prey to the spider to alert her to its presence and location; protect the spider from predators and parasitoids; minimize the web's visibility to prey; provide a path by which the spider can reach the prey and that will support her weight and minimize the damage she produces as she moves; minimize the cost (in both material and behavior) of building the web; and (possibly) attract prey. Most important is that it's not possible to optimize all functions for different prey with a single design. A design that's likely to improve one function is likely to impair other functions. These discussions of possible functions based on the mechanical properties of silk provide a basis with which to re-examine several empirical patterns in the designs of orb webs.

Orb (optics)

Visibility

10.7208/chicago/9780226534749.003.0004

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