Courtship

Then follows a set of complicated behavioral responses (called courtship). The apparent functions of these are to (1) assure each partner that the other can produce the best possible offspring with the greatest chance of survival, and (2) to coordinate copulation, or coitus. For many species, a particular pattern of behavior is required for completion of the sex act, and any disruption of this behavioral pattern will not lead to successful fertilization. 

Everything is incredible, if you can skin off the crust of obviousness our habit put on it. 

In all these rituals, the objective is successful mating and reproduction. Males and females assess each other for strength, health, and reproductive suitability. If at any time, one or the other partner does not perform in a satisfactory way, the courtship routine may be terminated and partners go off in search of other mates (or, in the case of the male spiders, they may be eaten). 

FIGURE 6.18.3 Coordinated activity during the courtship of the spined stickleback fish. (Redrawn from Lewis, D.B. and Gower, D.M., Biology of Communication, John Wiley Sons, New York, 1980.) 

FIGURE 6.18.4 This is a picture of Robert Ehrlich, his wife Kendel, and son Drew the morning after his election as governor of Maryland in 2002. Notice the similarity in facial features between the man and his wife. The opposite of the marriage of two people with similar facial features has been ealled interfacial marriage. (Photo courtesy of Kim Hairston/T/ie Baltimore Sun.) 

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Courtship rituals in fish can involve a complex communication between males... 

The effects of EDCs on behavior in fish have been more extensively studied than in birds. Examples of the effects of EDCs seen in fish include profound alterations in courtship behavior in male guppies (Poecilia reticulate) exposed to vinclozolin and DDE, including at environmentally relevant concentrations (Baatrup and Junge 2001) and altered courtship behavior in three-spined stickleback exposed to environmentally relevant concentrations of EE2 (Bell 2001). In the stickleback studies, exposed males became less aggressive and had a reduced nesting activity, and this was linked with reduced concentrations of the male sex androgen 11-ketotestosterone. Recently,... 

Bell, A.M. (2001). Effects of an endocrine disrupter on courtship and aggressive behaviour of male three-spined stickleback, Gasterosteus aculeatus. Animal Behaviour 62, 775-780. 

One well-analysed chemosignal system is that of the Red-bellied Newt (Cynops pyrrhogaster). Males of this species produce from the abdominal gland a semiochemical protein (sodefrin) with marked VNO activity as a female attractant (Kikuyama et al., 1997). Courtship displays of newts often contain tail-waving bouts, which direct cloacal or other secretions from the male toward female recipients (Fig. 3.1). A large stable molecule like sodefrin, alone or as part of a VNPr complex, is presumably suitable for such local transference. 

The chemoreceptive mechanisms in amphibia are undoubtedly worthy of further analysis, not only for their own sake, but to provide clues as to the origination of advanced chemosignal systems. As noted above, a pheromonal signal from the mental gland acts as a courtship/ receptivity inducer. The plethodontid receptivity factor (PRF) (Chap. 3) despite its size (22 kD), seems to have been converted from its internal role as an inter-cellular cytokine, to an inter-individual coordinator of reproductive activity (Rollmann et al., 1999). Endocrine or... 

Amongst amphibia, chemosignalling is most prominent as part of mate location, courtship and mating (Chaps. 2 and 3). Social usage of... 

Feldhoff R.C., Rollman S.M. and Houck L.D. (1999). Chemical analysis of courtship pheromones in a Plethodontid Salamander. In Advances in Chemical Signals in Vertebrates (Johnston R.E., Miiller-Schwarze D. and Sorenson P., eds.). Kluwer, New York, pp. 117-126. 

Kubie J.L., Vagvolgyi A. and Halpem M. (1978). Roles of the vomeronasal and olfactory systems in courtship behavior of male Garter snakes. J Comp Physiol Psychol 92, 627-641. 

Parrott R. (1978). Courtship and copulation in pre-pubertally castrated male sheep (wethers) treated with 17a-estradiol, aromatisable androgens or DHT. Horn Behav 11, 20-27. 

Some male arctiid moths produce their courtship pheromone from dietary pyrrolizidine alkaloids acquired during feeding by the larvae [ 126]. Conversion of monocrotaline to hydroxydanaidal by males is accomplished by aromatiza-tion, ester hydrolysis and oxidation of an alcohol to the aldehyde [7]. In the case of Utetheisa ornatirx the stereo-configuration at C7 of the dietary alkaloid is the same as the pheromone released (R). In contrast, another arctiid, Creatono-tos transiens, can convert a dietary precursor alkaloid with the (S) configuration at C7 (heliotrine) to (l )-hydroxydanaidal. The biosynthesis occurs by first oxidation-reduction at C7 to convert the stereochemistry and then proceeds through aromatization, hydrolysis, and oxidation [7]. 

Pheromones are used as sex attractants in courtship, warning substances, or aggregation compounds (to cause members of their species to congregate). 

These cues are important in rearing, territorial, courtship and, in particular, sexual behaviors. The vomeronasal organ (VNO) is separate from the main epithelium in mammals, comprising a thin epithelial tissue within a bony capsule in the lateral wall of the nasal cavity. It is probably vestigial in humans. The VNO epithelium contains at least two populations of microvillar chemosensory neurons one is in the more apical aspects of the epithelium, while the other lies in the more basal region. These two populations of vomeronasal neurons (VNs) are defined by the differential expression of several genes. For example, the apical VNs express the G-protein subunit Ga, while the basal neurons express Ga0. Apical and basal VNs also... 

No. 8 shot (72 mg) Mortality 24% in 4 weeks normal courtship and reproductive activities, but egg hatching significantly reduced lead residues elevated in kidney, liver, and bone 36... 

The function of the male courtship pheromone in plethodontids was first documented in a study of Desmognathus ocoee Houck and Reagan (1990) showed that the diffusion delivery of a crude extract from the male pheromone gland increased... 

After 30 min, a deglanded male was added to each courtship box, and a combination of scan and focal sampling was used to record all occurrences of courtship behaviours. These behaviours included the time of the first occurrence of the male orienting to and physically contacting the female, and the time when the male completed spermatophore deposition. The same male-female pair was observed on a subsequent night when the female received a treatment (saline control or pheromone extract) that was different from the treatment she received on an earlier trial. In this way, each male-female pair was its own control. On each trial night, equal numbers of females were treated with each solution. 

Courtship duration was defined as the time from first tactile contact (typically the male contacting the female) until spermatophore deposition was completed. We selected spermatophore deposition as the end of courtship because (a) this is a distinct behaviour that any observer can score, (b) the time between spermatophore deposition and insemination typically is only 1-2 min, and (c) some females do not get inseminated (e.g., walk past the spermatophore) and so the end of courtship would be ambiguous for these females. In addition, treatment (pheromone or saline) was not correlated with insemination success for D. ocoee, given that a pair reached the spermatophore deposition stage (Houck, unpublished data). 

Twenty male-female pairs each mated on two different trial nights, once with a pheromone treatment (the 20-25 kDa fraction of the male courtship pheromone) and once with a saline treatment (n = 20 paired values). The duration of courtship was reduced significantly when pairs were treated with the pheromone fraction vs the saline control (t = 1.73, df= 19, P < 0.02). For these 20 pairs, the average courtship duration was 54 min when treated with the pheromone fraction, and 70 min when treated with the saline control. Thus, the control treatment resulted in courtships that were approximately 30% longer. 

In the plethodontid salamander D. ocoee, courtship duration was reduced for male-female pairs in which the female received a protein signal from the 20-25 kDa fraction of the male courtship pheromone. We interpret this reduction in courtship duration as an increase in receptivity for females receiving the pheromone. 

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