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1.
Condition-dependent control of paternity by female purple martins: implications for coloniality 总被引:9,自引:0,他引:9
Proposed causal links between extra-pair copulation (EPC) and colony formation in socially monogamous birds hinge on the
question of which sex controls fertilizations. We examined in colonial purple martins Progne subis (1) whether EPCs were forced or accepted by females, and (2) the degree to which apparently receptive females were able to
obtain EPCs against their mates’ paternity defenses. Paternity analyses of multilocus DNA fingerprinting confirmed previous
findings of a marked relationship between age class and extra-pair fertilizations (EPFs), with young males losing paternity
of 43% (n = 53) of their putative offspring compared to 4% (n = 85) by old males. All assignable extra-pair offspring were sired by old males, with one male obtaining most EPFs each year.
Contrary to the hypothesis that EPCs are forced, EPF frequency within age class did not increase with seasonal increases in
the number of males per fertile female. Whereas the male control hypothesis predicted that the male age class that mate-guarded
more would be cuckolded less, the reverse was true: young males guarded significantly more intensely. The male age class difference
in cuckoldry could not be explained by the possibility that young and inexperienced females (which are usually paired to young
males) were more vulnerable to forced copulation because EPFs were unrelated to female age. These findings suggest that females
(1) pair with old males and avoid EPCs, or (2) pursue a mixed mating strategy of pairing with young males and accepting EPCs
from old males. The receptivity to EPCs by females paired to young males put them in conflict with their mates. Two factors
determined the paternity achieved by young males: (1) the relative size of the male to the female, with young males achieving
much higher paternity when they were larger than their mates, and (2) the intensity of mate-guarding. Both variables together
explained 77% of the variance in paternity and are each aspects of male-female conflict. Given female receptivity to EPCs,
mate-guarding can be viewed as male interference with female mating strategies. We conclude that EPCs are rarely or never
forced, but the opportunity for females paired to young males to obtain EPCs is relative to the ability of their mates to
prevent them from encountering other males. Evidence of mixed mating strategies by females, combined with other features of
the martin mating system, is consistent with the female-driven “hidden lek hypothesis” of colony formation which predicts
that males are drawn to colonies when females seek extra-pair copulations.
Received: 23 March 1995/Accepted after revision: 14 January 1996 相似文献
2.
Behaviorally dominant nestlings routinely kill sibling nestmates in blue-footed booby (Sula nebouxii) broods during periods of food shortage. Previous work demonstrated that these dominant, first-hatching “A-chicks” regulate
the lethality of their behavior towards subordinate, second-hatching “B-chicks,” showing tolerance towards B-chicks except
during chronic food shortages. Siblicide by A-chicks usually occurs after the hatchling stage. Results of an interspecific
cross-fostering experiment indicated that A-chicks also attempt siblicide shortly after hatching, but parents apparently exert
control over these attempts, and thwart them, when chicks are young. Theory predicts selection for such regulation in siblicidal
birds that are likely to experience genetic parent-offspring conflict over the value of subordinant nestlings; our evidence
of post-hatching parental regulation is consistent with that prediction.
Received: 6 June 1998 / Accepted after revision: 12 July 1998 相似文献
3.
James S. Quinn Glen E. Woolfenden John W. Fitzpatrick Bradley N. White 《Behavioral ecology and sociobiology》1999,45(1):1-10
Extensive behavioural and pedigree data on a colour-marked population of Florida scrub-jays (Aphelocoma coerulescens) suggested that this cooperatively breeding species is monogamous, with extremely rare exceptions in which males have two
mates. We used multi-locus DNA fingerprinting to test these observations by determining genetic parentage. Despite restricted
dispersal and high relatedness between behavioural parents and non-breeding members of the group, DNA fingerprints provided
sufficient variability to determine parentage unambiguously in almost all cases. We found no evidence of extra-pair fertilisation
of females or egg dumping, and confirmed a suspected case of polygyny in which a mother and daughter laid and incubated in
the same nest. Our results confirm that detailed behavioural data allow accurate assignment of genetic parentage in this species.
In Florida scrub-jays, large territory size may limit opportunities for cuckoldry, and persistent intense competition for
limited breeding space may lead to low variance in the quality of established male breeders. These factors would reduce both
the opportunity for, and benefits of engaging in extra-pair fertilisations. Delayed dispersal and cooperative breeding in
this species have not evolved as avenues for direct reproduction by unpaired individuals.
Received: 25 May 1998 / Accepted after revision: 26 June 1998 相似文献
4.
Frequency and timing of extrapair fertilisation in the polyandrous red phalarope (Phalaropus fulicarius) 总被引:1,自引:0,他引:1
James Dale Robert Montgomerie Denise Michaud Peter Boag 《Behavioral ecology and sociobiology》1999,46(1):50-56
In sequentially polyandrous bird species, where females mate with different males in succession during a single breeding
season, sperm stored by females can occasionally lead to extrapair fertilisations (EPFs) in clutches cared for by the second
and subsequent males. Thus, we predicted that in red phalaropes (Phalaropus fulicarius) – a sex-role-reversed, sequentially polyandrous, arctic breeding shorebird – EPFs would occur more frequently in clutches
laid later in the breeding season. We used multilocus DNA profiling to examine the frequency and timing of EPFs in a population
of red phalaropes breeding in the Canadian high arctic. Using a technique to determine parentage without maternal DNA, we
inferred that 6 of 70 chicks in 18 broods resulted from EPFs – one extrapair chick in each of 6 broods. These results were
supported by a further analysis using microsatellite DNA. As predicted, broods containing EPFs hatched from clutches laid
significantly later in the season than did broods containing no EPFs. The difference in median hatch dates between broods
with and without EPFs was 9.0 days, or 38% of the entire egg-laying period in that season. For the whole breeding season,
we estimated that 6.5% of chicks were sired by extrapair males, which is similar to extrapair paternity estimates for other
sex-role-reversed birds, but relatively low compared to the majority of socially monogamous species studied so far.
Received: 24 August 1998 / Received in revised form: 18 January 1999 / Accepted: 24 January 1999 相似文献
5.
Extra-pair paternity in the monogamous Alpine marmot revealed by nuclear DNA microsatellite analysis 总被引:8,自引:0,他引:8
Benoît Goossens Laurent Graziani Lisette P. Waits Etienne Farand Séverine Magnolon Jacques Coulon Marie-Claude Bel Pierre Taberlet Dominique Allainé 《Behavioral ecology and sociobiology》1998,43(4-5):281-288
The genetic parentage and pedigrees of 35 litters from 12 family groups of monogamous Alpine marmot (Marmota marmota) in the French Alps were analyzed using six hypervariable sequence repeat nuclear loci (microsatellites). All of the members
of these family groups were sampled during a 5-year period. Hairs taken directly from animals served as a source of DNA for
amplification of the loci. Our results indicate that the genetic mating system of the Alpine marmot is quite different from
a strictly monogamous breeding system. Extra-pair paternity occurred in 11 of the 35 litters (31.4%). Of the 134 juveniles
typed, 26 (19.4%) could be attributed to extra-pair copulation (EPC). We examine hypotheses which could explain the evolution
of EPC and discuss the different patterns of extra-pair mating.
Received: 11 July 1997 / Accepted after revision: 23 May 1998 相似文献
6.
Corey R. Freeman-Gallant 《Behavioral ecology and sociobiology》1997,40(6):395-400
Empirical relationships between parentage and male parental care are commonly interpreted in the context of life-history
models that consider increased offspring survivorship as the only benefit of paternal effort. However, indirect benefits associated
with male care can also influence a male's response to cuckoldry: if females allocate paternity according to their prior experience
with male parental care, it may pay for males to provision extra-pair young in early broods. Here, I assess the relationship
between first-brood parentage and paternal care in a population of Savannah sparrows (Passerculussandwichensis) where a male's fertilization success in the second brood appears to be influenced by his prior parental performance. Based
on the multi-locus DNA fingerprinting of 17 first broods, male feeding effort was influenced by parentage (percent of brood
resulting from within-pair fertilizations) but not by brood size, male mating status (monogamous versus polygynous), timing
of breeding (hatching date), structural size (wing length) or condition (mass). Males provided more care to broods that contained
few within-pair young. This result supports the idea that males provision young to increase their future mating success, but
alternative hypotheses involving male quality and timing of breeding cannot be excluded.
Received: 13 August 1996 / Accepted after revision: 22 February 1997 相似文献
7.
Bo Terning Hansen Lars Erik Johannessen Tore Slagsvold 《Behavioral ecology and sociobiology》2007,61(8):1203-1209
Imprinting plays a key role in the development of species recognition, with young imprinting upon the morphological characters
of their parents. However, the potential role that cultural transmission might play in species recognition remains largely
uninvestigated. Great tits (Parus major) and blue tits (Cyanistes caeruleus) do not normally perceive each other as sexual competitors or potential partners. However, after reciprocal interspecific
cross-fostering, both species may perceive individuals of the foster species as potential rivals or mates. Although the experience
of being raised by heterospecifics clearly has affected the species recognition of cross-fostered birds, some of them breed
naturally with conspecifics. The offspring of such cross-fostered birds (OCF) are hence raised by parents that look like ordinary
conspecifics but display deviant species recognition as compared to controls in terms of aggressive response towards rivals.
Comparing the aggressive behavior of OCF, cross-fostered birds and controls towards territorial intruders may thus help tease
apart the influence of morphological vs behavioral cues of parents in the development of offspring species recognition. To
this end, we compared birds from all three treatments with respect to their aggressive response to territorial intruders of
both species during the breeding season. OCF and controls did not differ in their pattern of response towards heterospecific
and conspecific stimuli. Compared to cross-fostered birds, OCF and controls showed less aggression towards heterospecific
intruders, while the response towards conspecific intruders did not differ between treatments. These results demonstrate that
both tit species imprint on the morphological characters of their parents, but that parental behavior is not important for
the development of species recognition in terms of aggressive response towards territorial intruders. 相似文献
8.
Seasonally breeding predators, which are limited in the time available for provisioning young at a central location, and
by the fasting abilities of the young, are likely to maximize energy delivery to the young by maximizing the rate of energy
delivery averaged over the whole period of investment. Reduction in food availability or increased foraging costs will alter
the optimal behavior of individuals. This study examined the behavioral adaptations of a diving predator, the Antarctic fur
seal, to increased foraging costs during lactation. One group of mothers (n=5, treatment) was fitted with additional drag to increase the cost of transport in comparison with a control group (n=8). At the scales of the individual dives, the treatment group made more shorter, shallower (< 30 m) dives. Compensation for
slower swimming speeds was achieved by diving at a steeper angle. Overall, diving behavior conformed to several specific theoretical
predictions but there were also departures from theory, particularly concerning swimming speed during diving. Diving behavior
appears to be adjusted to maximize the proportion of time spent at the bottom of dives. At the scale of diving bouts, no difference
was observed between the treatment and control groups in terms of the frequency and duration of bouts and there was also no
difference between the two groups in terms of the proportion of time spent diving. At the scale of complete foraging cycles,
time taken to return to the pup was significantly longer in the treatment group but there was no difference in the rate of
delivery of energy (measured from pup growth rate) to the pups in each group. Since mothers in the treatment group did not
use significantly more body reserves, we conclude that behavioral adjustments at the scale of individual dives allowed mothers
in the treatment group to compensate for the additional foraging costs. Pup growth rate appears to be less sensitive to the
foraging conditions experienced by mothers than foraging trip duration.
Received: 14 June 1996 / Accepted after revision: 16 November 1996 相似文献
9.
Ethan D. Clotfelter 《Behavioral ecology and sociobiology》1997,41(3):193-201
Parental investment by red-winged blackbirds (Agelaius phoeniceus) in response to natural and experi‐mental parasitism by brown-headed cowbirds (Molothrus ater), and in response to freeze-dried, female cowbird mounts presented near redwing nests during the egg-laying period was measured.
Two measures of redwing parental investment were used: nest defense effort toward a model predator, and rate of feeding nestlings.
There were no significant differences in levels of parental investment among unparasitized nests, naturally parasitized nests,
or experimentally parasitized nests. Similarly, parental investment did not differ between redwings that were exposed to the
cowbird mount and those that were not exposed to the mount, or among redwings exposed to the cowbird mount at different distances
from the nest. This suggests that red-winged blackbirds do not recognize when they have been parasitized, and hence do not
associate parasitism with a decrease in their parentage, or that parentage is not an important predictor of parental investment
in this species.
Received: 24 January 1997 / Accepted after revision: 7 June 1997 相似文献
10.
All other things being equal, the lifetime reproductive success (LRS) of iteroparous and semelparous individuals should scale
with the number of breeding seasons. Deviations from this relationship may occur for many reasons, including age- or size-related
fecundity or life history trade-offs, which may differ between sexes. We used 19 brood years of DNA parentage analysis in
a small (N = 4–143 year−1) wild, unexploited population of steelhead trout (Oncorhynchus mykiss) to compare the LRS of individuals that spawned only once [“one time spawners” (OTS), N = 355 male, 371 female] to those spawning twice [“repeat spawners” (RPS), N = 13 male, 49 female]. Female RPS had nearly twice the LRS of female OTS (1.17 offspring per female vs 0.91 offspring per
female), whereas male RPS had nearly three times the LRS of male OTS (1.54 offspring per male vs 0.57 offspring per male).
Female RPS produced slightly more adult offspring during their second breeding season than their first (0.78 vs 0.82 offspring
per female); however, male RPS produced all of their adult offspring in their second breeding season (0 vs 1.54 offspring
per male). The additional growth in body size of males between breeding seasons may give them an advantage in their second
breeding season, but the lack of offspring produced in their first season suggests a trade-off between survival and future
reproduction that was not expressed in females. 相似文献
11.
Division of labor between undertaker specialists and other middle-aged workers in honey bee colonies
Stephen T. Trumbo Zhi-Yong Huang Gene E. Robinson 《Behavioral ecology and sociobiology》1997,41(3):151-163
A primary determinant of colony organization in temporally polyethic insect societies is inter-individual variation in behavior
that is independent of worker age. We examined behavioral repertoires, behavioral correlates of adult development, and spatial
distributions within the hive to explore the mechanisms that produce behavioral variation among middle-age honey bees (Apis mellifera). Individually labeled undertakers, guards, food storers, and wax workers exhibited a broad range of task-related behavior,
but bees tagged as undertakers were more likely to subsequently remove a corpse from the hive and handle a corpse compared
to other middle-aged bees. The activity level of undertakers was similar to other task groups, suggesting that undertaking
specialists were neither hyper-active “elites” nor quiescent “reserves” that become active only when a dead bee stimulus is
present. Undertakers also were more likely to remove debris and to remain in the lower region of the hive or near the entrance,
even when not engaged in corpse removal; both preferences may promote colony efficiency by reducing inter-task travel times.
Guards and undertakers were less likely to perform behavior normally associated with young bees compared to food storers and
wax workers. Undertakers and guards also initiated foraging at earlier ages than the other task groups. These results suggest
that undertakers and guards may be slightly developmentally advanced compared to food storers and wax workers. There also
was evidence for lifetime differences in behavioral preferences which could not be explained by differences in adult development.
Bees tagged as undertakers were more likely to subsequently remove a dead bee during their entire pre-foraging career compared
to other task groups or members of their general age cohort. Differences in both the rate of adult development and individual
behavioral preferences, both of which may be subject to genetic and environmental influences, are important determinants of
inter-individual variation among honey bees of middle age.
Received: 5 February 1997 / Accepted after revision: 27 May 1997 相似文献
12.
Historically, most mammals have been classified as polygynous; although recent molecular evidence suggests that many mammals
may be polygynandrous, particularly the ground-dwelling sciurids. We genotyped 351 round-tailed ground squirrels (Xerospermophilus tereticaudus) using seven microsatellite loci to determine paternity in 31 litters from 2004 to 2007. Polygyny was evident in all years
except in 2007, when the population size was reduced. Multiple paternity occurred in the majority of litters (55%) with 2.5 ± 0.26
sires/litter (n = 31). Forty-nine percent of resident males (n = 114) sired offspring, and of males that sired offspring (n = 56) 27% sired young in multiple litters in a single breeding season. Litter size was positively correlated with the number
of sires. Through an indirect analysis of paternity, we found 21 litters (68%) with an average relatedness of 0.5 or less.
Males had a greater opportunity for sexual selection (I
s = 1.60) than females (I
s = 0.40); Bateman’s gradient was also greater in males (1.07 ± 0.04, n = 56) than females (0.82 ± 0.08, n = 31). The mating system in round-tailed ground squirrels defined through genetic analyses and Bateman’s gradients is polygynandrous
compared to the previously suggested polygynous mating system as established by behavioral observations and fits within the
predictions of the ground squirrel sociality models. Upon evaluating the predictions of the sociality models among sciurid
species, we found a negative relationship between the level of sociality with litter size and the average percentage of multiple
paternity within a litter. Thus, recent genetic information and reclassification of mating systems support the predictions
of the ground-dwelling squirrel sociality models. 相似文献
13.
D. W. James 《Marine Biology》2000,137(5-6):913-923
The density, diet, movement, and covering behavior of Toxopneustes roseus (Agassiz) were investigated in rhodolith beds in the Gulf of California. Densities varied from a mean of 0.4 to 1.8/20 m2 with most urchins occurring in aggregations. Spatial patterns of urchins varied with depth, with greatest abundance at intermediate
depths (7.5–9.4 m) in the middle of the rhodolith bed. Urchins ate rhodoliths and nongeniculate coralline algal crusts almost
exclusively, despite the availability of other algae. The mean amounts ingested were 3.87 and 7.96 g carbonate/individual
per day. Even when food was abundant, animals were highly mobile, moving an average of 6.6–11.7 cm/h depending on site and
time of day. Diel movement may be a behavioral adaptation to avoid surge, which is greatest during the day. Covering behavior
may also be related to surge, as the ratio of covering material:body weight and the percent cover of material held were highest
at the site with the most surge. While an urchin consumed rhodoliths, its movement spread the grazing impact over large areas.
Bioturbation resulting from urchin feeding, movement, and covering activity probably benefits the rhodoliths by turning them,
which maintains rhodolith integrity, prevents fouling, and contributes to bed persistence.
Received: 22 February 1999 / Accepted: 3 July 2000 相似文献
14.
Profiles of diarrhetic shellfish poisoning (DSP) toxins produced throughout the growth cycle and the cell cycle of the toxigenic
marine dinoflagellate Prorocentrum lima were studied in triplicate unialgal batch cultures. Cells were pre-conditioned at 18 ± 1 °C, under a photon flux density
(PFD) of 90 ± 5 μmol m−2 s−1 on a 14 h light:10 h dark photoperiod. In exponential growth phase, cultures were synchronized in darkness for 17 d. After
dark synchronization, cultures were transferred back to the original photoperiod regime. Cells were harvested for DSP toxin
analysis by LC-MS (liquid chromatography with mass spectrometry), and double-stranded (nuclear) DNA was quantified by flow
cytometry. The cell populations became asynchronous within approximately 3 d after transition from darkness to the 14 h light:10 h
dark photoperiod. This may be due to the prolonged division cycle (5 to 7 d) that is not tightly phased by the photoperiod.
Unlike other planktonic Prorocentrum spp., cytokinesis in P. lima occurred early in the dark and ceased by “midnight”. Cellular levels of the four principal DSP toxins, okadaic acid (OA),
OA C8-diol-ester (OA-D8), dinophysistoxin-1 (DTX1) and dinophysistoxin-4 (DTX4), ranged from 0.37 to 6.6, 0.02 to 1.5, 0.04
to 2.6, and 1.8 to 7.8 fmol cell−1, respectively. No toxin production was evident during the extended period of dark synchronization nor during the initial
period when NH4 was consumed as the major nitrogen source. Soon after the cells were returned to the 14 h light:10 h dark cycle and they
began to take up NO3, cellular levels of all four toxins gradually increased. This increase in DSP toxins usually occurred in the light, marked
by a rise in DTX4 levels that preceded an increase in the cellular concentration of OA and DTX1 (delayed by 3 to 6 h). Thus,
DTX4 synthesis is initiated in the G1 phase of the cell cycle and persists into S phase (“morning” of the photoperiod), whereas
OA and DTX1 production occurs later during S and G2 phases (“afternoon”). No toxin production was measured during cytokinesis,
which happened early in the dark. The evidence indicates that toxin synthesis is restricted to the light period and is coupled
to cell cycle events.
Received: 3 September 1998 / Accepted: 30 March 1999 相似文献
15.
We examined the social organization and reproductive pattern of a population of Sparisoma cretense L. at Lampedusa Island (Italy). During the breeding season (July to September) individuals occur either in territorial or
in non-territorial groups, which quantitatively differ with respect to use of space, sex-ratio and sexual activity. Territorial
groups consist of one male plus one to three females, whereas in non-territorial groups as many as 54 fish share a common
area. Among non-territorial groups, variations, in both sex-ratio and behavior, suggest they could represent either feeding
aggregations or reproductive aggregations. Spawning, always in pairs, occurs daily in a short period of time before dusk and
has been observed only in territorial groups. Group spawning has never been observed, but another alternative mating tactic,
streaking on pair spawning, was recorded. In the non-breeding season fish do not aggregate in organized social units. Histological
examination of gonads showed that adults are larger than 12 cm total length. Females have an asynchronous ovary, typical of
species spawning several times during the breeding season. Males show secondary testes, indicating that their gonads develop
ovaries as juveniles, which are later redifferentiated into functional testes. Histological and demographic data seem to indicate
that, as in other species of this genus, prematurational sex-change occurs. The sexual pattern appears to be essentially gonochoristic,
but the potential for sex-change is not excluded.
Received: 5 January 1999 / Accepted: 22 June 1999 相似文献
16.
Correlates of extra-pair fertilization success in hooded warblers 总被引:13,自引:0,他引:13
Bridget J. M. Stutchbury W. H. Piper D. L. Neudorf S. A. Tarof Judith M. Rhymer G. Fuller R. C. Fleischer 《Behavioral ecology and sociobiology》1997,40(2):119-126
We examined correlates of extra-pair fertilization (EPF) success in the hooded warbler (Wilsonia citrina), a species where females pursue extra-pair matings. The good genes hypothesis predicts that females choose extra-pair mates
with morphological or behavioral traits that reflect differences in male genetic quality. EPFs were common, as 35.3% (42/119)
of broods contained extra-pair young (EPY) and 26.7% (95/356) of nestlings were the result of EPFs. There was a strong skew
in male EPF success which increased the variance in annual male mating success 2–3 fold. However, male morphology did not
predict EPF success, as extra-pair males were not older or larger than the males they cuckolded. Likewise, there were no significant
correlations between the proportion of extra-pair young in a brood and male size or age. The good genes hypothesis predicts
that high-quality males will be consistently preferred as genetic mates, but the number of young sired by a male with his
social mate was not consistent from one year to the next. There was a significant negative correlation between female age
and proportion of EPY produced, which could result if older females obtain higher-quality social mates. We found no strong
evidence that females choose extra-pair mates for good genes, but females may use behavioral rather than morphological cues
to assess relative male quality.
Received: 31 May 1996 / Accepted after revision: 17 October 1996 相似文献
17.
B. Birgersson 《Behavioral ecology and sociobiology》1998,43(2):87-93
This study tested whether fallow deer mothers, Dama dama, bias their investment towards sons and, thus, whether sons are more costly to produce than daughters. Young (2 years) and
old (≥3 years) hinds were analysed separately. Old hinds who raised sons accumulated less body mass than those who raised
daughters, during the period between late gestation and the end of lactation. This difference in body mass persisted to the
following spring. Mothers who had raised sons gave birth later and their offspring's pre-winter mass was lower the following
year than for mothers who had raised daughters. These results indicate higher expenditure for hinds who raise sons and support
theories of male-biased maternal investment. However, young mothers with sons and those with daughters did not differ in reproductive
performance the following year. One reason might be that young mothers are close to the maximum level of maternal expenditure,
since they are still growing, and cannot invest any extra resources in sons.
Received: 28 August 1997 / Accepted after revision: 5 April 1998 相似文献
18.
Jason Munshi-South 《Behavioral ecology and sociobiology》2007,62(2):201-212
Monogamy is rare in mammals (<5% spp.) but occurs in greater frequency among primates (15%) and their close relatives, the
treeshrews (100%; Order: Scandentia). Two genetic studies of parentage in monogamous primates revealed high rates of extra-pair
paternity (EPP), but to date parentage has not been studied in a treeshrew species. I analyzed the genetic parentage of 22
offspring from two populations of large treeshrews in Sabah, Malaysia (NE Borneo), using seven autosomal microsatellite loci
and one mitochondrial DNA marker. Half of these offspring were sired by males that were not the presumed partner of the mother
(50% EPP), and three litters exhibited evidence of multiple paternity. However, comparative analysis indicated that the high
rate of EPP in Tupaia tana is not associated with intense sperm competition. Relative testis size of treeshrews was similar to testis size in 22 primate
species with uni-male mating systems but smaller than 44 primates with multi-male mating systems. After factoring out the
effects of body size and phylogeny, I also found that the evolution of multi-male mating systems was significantly associated
with the evolution of larger testis size. Male–female pairs of T. tana occupy joint territories but forage and sleep alone (“dispersed pair-living”), and I argue that this form of behavioral monogamy
renders mate guarding ineffective. The adaptive advantages of behavioral monogamy likely differ from the advantages driving
EPP in large treeshrews. However, small testis size suggests that behavioral monogamy is not masking a dispersed multi-male
mating system in this species. 相似文献
19.
Symbiotic dinoflagellate algae (Symbiodinium sp.) isolated from the scleractinian coral Plesiastrea versipora and incubated in homogenized host tissue released 4 to 7 times as much glycerol (14 to 46 nmol glycerol/106 algae) as those incubated in seawater (3 to 6 nmol glycerol/106 algae) after 4 h incubation in the light. During this period, no release of triglycerides was detected. Intracellular glycerol
increased 2- to 3-fold in algae incubated in host homogenate, but remained unchanged in algae incubated in seawater at a concentration
of 0.82 ± 0.47 nmol glycerol/106 algae. In each incubation condition, intracellular triglyceride levels increased. However, in algae incubated in host homogenate,
the intracellular levels of triglycerides reached only about 75% of the amount reached in algae incubated in seawater (max.
18.55 ± 2.40 nmol glycerol/106 cells). Host homogenate did not stimulate the release of glycerol from algae during dark incubation. These data show that
the glycerol released by algae incubated in host-tissue homogenate was derived from increased synthesis of glycerol or from
diversion of some glycerol or other photosynthetic intermediates from incorporation into algal triglyceride stores, and did
not come from existing stores.
Received: 20 December 1996 / Accepted: 9 January 1997 相似文献
20.
The genetic mating system of a sex-role-reversed pipefish (Syngnathus typhle): a molecular inquiry 总被引:4,自引:0,他引:4
Adam G. Jones Gunilla Rosenqvist Anders Berglund John C. Avise 《Behavioral ecology and sociobiology》1999,46(5):357-365
In the pipefish Syngnathus typhle as in other species of Syngnathidae, developing embryos are reared on the male's ventral surface. Although much laboratory
research has been directed toward understanding sexual selection in this sex-role-reversed species, few studies have addressed
the mating behavior of S. typhle in the wild, and none has capitalized upon the power of molecular genetic assays. Here we present the first direct assessment
of the genetic mating system of S. typhle in nature. Novel microsatellite loci were cloned and characterized from this species, and employed to assay entire broods
from 30 pregnant, field-captured males. Genetic analysis of 1340 embryos revealed that 1–6 females (mean = 3.1) contributed
to each brooded clutch, the highest rate of multiple maternity yet documented in any pipefish. Evidence of multiple mating
by females was also detected. Thus, this population of S. typhle displays a polygynandrous mating system, a finding consistent with previous field and laboratory observations. Our results,
considered together with similar studies of other syngnathid species, provide preliminary support for the hypothesis that
the genetic mating system is related to the evolution of sexual dimorphism in the fish family Syngnathidae.
Received: 19 January 1999 / Received in revised form: 15 April 1999 / Accepted: 9 May 1999 相似文献