Animal Behavior - Chpt. 9 Reading Notes

Front 1

What are the four hypotheses regarding the female hyena pseudopenis and how have two of them been refuted?

Back 1

1. Extra Androgen Hypothesis: Development of the pseudopenis might be the result of exposure of the female to high levels of male sex hormones, because the male penis and the female clitoris develop from exactly the same embryonic tissues. If these tissues are exposed early on the male sex hormones, a penis is the end result. Gould thought it likely that female embryos in the spotted hyena must be exposed to unusual concentrations of male androgens. However, females administered an anti-androgenic chemical prenatally retained their elaborate pseudopenis.
4. Males could present their penis to the female and signal the suitor's male identity and thus his subordinate, nonthreatening status. Females may have come over time to respond to this signal with acceptance of the male's presence rather reacting with aggression
2.Another hypothesis is that hormones producing the pseudopenis produce other aggressive behaviors, allowing the hyenas to become more dominant. The extra-androgen-extra aggression hypothesis is at odds with the finding that adult male spotted hyenas are less aggressive than females despite having the same or higher androgen levels than females.
3.Other hypothesis is that the erect female genitalia were used to reduce tensions among the highly aggressive female members of the clan, promoting social bonds that keep the group together to work for the mutual benefit of all

Front 2

How do the sex hormones in female hyenas compare to those in males?

Back 2

FEmale spotted hyenas have circulating levels of testosterone equal to those of males; also have similar levels of a precursor of testosterone, called androstenedioine.

Front 3

What is the hyena pseudopenis used for?

Back 3

Communication

Front 4

What is the cost of the pseudopenis?

Back 4

10 to 20 percent of all females die the first time they attempt to give birth because their pups have to pass through the clitories, which is too small for this purpose

Front 5

What might be the benefits associated with a pseudopenis?

Back 5

Females with a pseudopenis have hormonal mechanisms that promote aggression; the young alpha females grow faster, are more likely to survive, and are more likely to become dominant themselves than tare the offspring of subordinate hyenas.

Front 6

Which evolved first, the female-dominant, male-subordinate relationship or the pseudopenis?

Back 6

The pseudopenis

Front 7

Why do male whistling moths produce loud ultrasonic pulses of sound by beating their knobbed wings together?

Back 7

Play a role in defense of a calling territory as well as in attracting receptive females to the caller.

Front 8

Describe the sound-receiving system in whistling moths.

Back 8

Outer ear is composed of a small ellipse of thin cuticle, called the tympanic membrane, which covers an air sac. When the membrane vibrates in response to ultrasound, the air sac also moves, supplying mechanical energy to associated sensory receptors.

Front 9

how do saturniid moths receive signals when they lack ears and cannot hear?

Back 9

Mechanoreceptor cells are attached to the saturniid thoracic cuticle, remarkably similar in structure to the mechanoreceptor cells in the ears of noctuid moths; involved modifications of existing sensory cells that peformed some other function for the earless moths

Front 10

What do the mechanoreceptors do fin saturniids?

Back 10

Translate mechanical energy from the motion of the cuticle into messages that are relayed elsewhere in the moth's nervous system, where information about the alignment of various body parts is used to adjust the moths' position in space