|
| |
EXTRA-PAIR COPULATIONS IN SONGBIRDS.
Term Paper ID:23698
|
|
|
Essay Subject:
Causes, effects, frequency, theories & examples of females' mating with more than one male.... More...
|
5 Pages / 1125 Words
11 sources, 12 Citations,
APA Format
$20.00
Return to List of Papers
|
Paper Abstract:
Causes, effects, frequency, theories & examples of females' mating with more than one male.
Paper Introduction:
EXTRA-PAIR COPULATIONS IN SONGBIRDS
Introduction
Studies demonstrate that female birds engage in copulations with males other than their mate and these extra-pair copulations (EPCs) may result in extra-pair fertilizations. The frequency of extra-pair paternity varies among populations or years within the same species. The question remains, regarding why females mate with more than one male (Dunn, Robertson, Michaud-Freeman, & Boag, 1994). To answer this question, researchers attempt to determine factors related to EPCs and propose theories regarding EPCs. Naturalistic, observational, and experimental studies confirm hypotheses regarding prevalence, adaptive functioning, sexual selection, and fledgling adoption.
Extra-pair Copulation Frequency
Text of the Paper:
The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper.
Attractive males have higher song rates,songs with higher song rates, and fledge heavier offspring; this isconsistent with a good genes model of sexual selection (Burley, Enstrom, &Chitwood, 1994; Houtman, 1992). & Robertson, R. P. Extra-pair relations in zebra finches: differential male success results from female tactics. Ecol., 6, 27-38.Houtman, A. J. Behav. T. (1993). Males provision their young at a similar rate to the females;males with illegitimate offspring did not reduce provisioning efforts.Since females received nothing but sperm from extra-pair copulation,behaviors are presumed consistent with female choice for male geneticquality. Ecol. These results are compared tonestbox studies of tree swallows which show that 5 - 87 percent broodscontained extra-pair young with males fathering 38 - 53 percent of young.Natural conditions demonstrate greater proportions of extra-pair young thannestboxes, however, frequency of extra-pair paternity was not significantlydifferent. Genetic analyses ofparentage in many avain species, previously assumed to be monogamous,demonstrates that EPCs account for high percentages of offspring. Lifjeld, Dunn,Robertson, and Boag (1993) studied monogamous pairs of tree swallows.Females copulated often with their own mate but were never seen copulatingwith other males. J., Michaud-Freeman, D., & Boag, P. Sociobiol., 27, 315-324.Burley, N. REFERENCESBarber, C. & Robertson, R. (1996). Zebra finches breed in colonies, aremonogamous, and sexually dimorphic. Proc. Ecol., 5, 384-392.----------------------- 8 Behav. (1994). M., & Krupa, A. Behav. Behavioral observationdemonstrated that extra-pair parenting occurred through extra-paircopulation and not rapid mate switching. O., Robertson, R. Animal Behavior, 45, 213-229.Stutchbury, B. M. Female zebra finches choose extra-pair copulationswith genetically attractive males. Behav. Ecol. O. The authors studied tree swallows and reported thatunfaithful females copulate with their mate similarly to the rates offaithful females, however, unfaithful females have a majority of offspringsired by extra-pair males. (1993). Extra-pair young were more frequentin first broods and the proportion within a brood was strongly bimodalamong broods. J., & Boag, P. T. Lifjeld and Robertson (1992) demonstrated female control of extra-pair copulation. Conclusions Research demonstrates the prevalence of EPCs in the monogamoussongbird and lends support to the theory that females appear to control theselection of males for genetically beneficial reasons. J. Soc. DNA fingerprinting revealed that 47 percent females hadextrapair young in their first or second brood and 29 percent were theresult of extra-pair fertilizations. EXTRA-PAIR COPULATIONS IN SONGBIRDS Introduction Studies demonstrate that female birds engage in copulations withmales other than their mate and these extra-pair copulations (EPCs) mayresult in extra-pair fertilizations. J. Extra-pair paternity and intraspecific brood parasitism in wild zebra finches Taeniopygia guttata, revealed by DNA fingerprinting. Ecol. An extrapair-paternity hypothesis for adoption, suggests that fledgling adoption mayresult from extrapair matings; the adopting bird may be the genetic parentof the fledgling it adopts. Extra-pair Copulation Frequency DNA fingerprinting is used to examine the frequency of extra-paircopulation. The authors found ten cases of extra-pair parentage (1 .9percent of offspring or 36 percent of broods). (1992). Female tactics are assumed to bedetermined by fitness benefits of having offspring sired by specific males. In this case the female mightpassively accept an EPC. J. To answer this question,researchers attempt to determine factors related to EPCs and proposetheories regarding EPCs. (1994). J., Rhymer, J. Fledgling adoption in hooded warblers (Wilsonia citrina): does extrapair paternity play a role? The females display active choice ofextra-pair copulatory partners and employ conditional tactics to obtainthese partners. Adaptive Significance & Sexual Selection The study of adaptive significance of extra-pair copulations includesthe extent that the copulations result in fertilization. S. T., Enstrom, D. Animal Behavior, 45, 231-239.Dunn, P. & Ogden, L. Sociobiol., 35, 273-281.Hasselquist, D., Bensch, S., & von Schantz, T. The questionremains, regarding why females mate with more than one male (Dunn,Robertson, Michaud-Freeman, & Boag, 1994). Female control of extra-pairfertilization in tree swallows. Behav. Adjacent male neighbors were sometimes identified as thefather. Future efforts towardunderstanding why females mate with more than one male, need to includeexplorations of these and other questions. Sociobiol., 38, 425-43 .Birkhead, T. Naturalistic, observational, and experimentalstudies confirm hypotheses regarding prevalence, adaptive functioning,sexual selection, and fledgling adoption. R., Burke, T., Zann, R., Hunter, F. M., & Morton, E. Stutchbury, Rhymer, and Morton (1994) report their findingsregarding extra-pair fertilizations of the hooded warbler, a monogamoussongbird. Sociobiol., 31, 89-96.Lifjeld, J. DNAfingerprinting and related techniques allow the measurement of eachindividual's contribution of gametes to the next generation; fitnessconsequences of mating strategies can be evaluated. T., Dunn, P. Ecol. Low frequency of extrapair paternity in the polygynous great reed warbler, Acrocephalus arundinaceus. EPCs & Fledgling Adoption Stutchbury and Ogden (1996) report that extrapair fertilizationsoccur in many Temperate Zone passerines, with high frequency. To solicit copulations, the female flattens out her bodyand shivers her tail sideways. T. R. Males can increase their mating success in monogamous birds byengaging in extra-pair copulations (Dunn & Robertson, 1993). The high frequencyof extra-pair paternity in tree swallows is not an artifact of nestboxes.Behav. Alternatively, the female might choose to haveEPCs with an attractive male (Houtman, 1992). Studies regarding frequency of extra-pair paternity are criticizeddue to their creation of artificial nesting conditions and breedingbehavior that might be different from that in natural conditions (nestboxstudies). J., & Boag, P. A., Robertson, R. E. Theyused DNA fingerprinting of Hooded Warblers and found that high rates ofextrapair fertilizations (36 percent of nestlings) occurring in thepopulation may increase average degrees of relatedness between a male andfledgling, however for this study, adoptive males were not the geneticfathers of the fledglings they adopted. The authors studied this possibility. A striking contrast was found between rates of extra-pair copulation and rates of extra-pair fertilization; no relationship wasfound between pair copulation rate and proportion of illegitimate young ina brood. Extrapair paternity in hooded warblers. (1993). A., & Chitwood, L. It was concluded that fertilization patternsappeared to be determined by the female, with active selection andrejection of copulation partners. For this reason, Barber, Robertson, and Boag (1996) studied 25families of tree swallows nesting in natural cavities to compare with anestbox population. Sexual selection for genetically based male traits may operate in amonogamous species by the more attractive male pairing with more fecundfemales; this is reported to be the case in the great tit and the swallow.Extra-pair copulations (EPCs) is another way that sexual selection forgenetic benefits may operate in a monogamous species. Lond., 249, 3-6.Lifjeld, J. (199 ). Extra-pair paternity in monogamous tree swallows. Field studies demonstrate that female zebra finches actively solicitand perform extra-pair copulations with males that are genetically moreattractive than their mates. (1996). (1994).Extra-pair paternity in tree swallows: why do females mate with more thanone male? Animal Behavior, 48, 1 31-1 41.Dunn, P. Extra-pair paternity in polygynoustree swallows. Birkhead, Burke, Zann, Hunter, and Krupa (199 ) studied 25zebra finch (Taeniopygia guttata) families, with 16 pairs of parents and 92offspring. Toachieve EPCs, a more dominant male may force EPCs on a female, oroutcompete her mate for access to her. The frequency of extra-pair paternityvaries among populations or years within the same species. The Auk, 113(1), 218-22 .Stutchbury, B. It was concluded that females benefit from extra-pair copulationsand have some control over which males obtain EPCs. T. Early studiessuggested that males harassed and forced copulation with females, howeverrecent studies find that females appear to gain from participating in extra-pair copulations and fertilizations (Hasselquist, Bensch, & von Schantz,1994). Extra-pair paternity is therefore not considered an artifact ofartificial nesting conditions. (1992). O., Robertson, R. Results showed that 84 percent of the females nestingin natural conditions obtained fertilizations from extra-pair males; thesemales fathered 69 percent of all nestlings. However, factorsinfluencing the distribution of EPCs are inconsistent, some studiesidentify male attractiveness features and others fail to present detectablephenotypic characteristics of males with high fertilization success.Additionally, studies demonstrate that where males become polygynous, thereis a low frequency of extra-pair fertilizations; this does not lend supportto concepts pertaining to female control of EPFs. DNA fingerprinting also revealsan increase in levels of extra-pair paternity from the previous year formonogamous tree swallows (Tachycineta bicolor); 5 percent of the broodshad extra-pair young in 199 , compared to 87 percent found in 1991 (Dunn,Robertson, Michaud-Freedman, Boag, 1994).
If this paper is not what you are looking for, you can search again:
or
Click here to request an essay written just for you.
|
|
|
