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1.
Claw loss and reversal of handedness during regeneration are common phenomena in heterochelous decapod crustaceans, which
typically have one large ‘crusher’ claw on the right side and a smaller ‘cutter’ claw on the left. Little is known about the
relative importance of claw growth vs. body growth during claw regeneration. Here the relationship between claw size and body
size of green crabs, Carcinus maenas, was examined to test for differences in claw allometry as a function of handedness and sex, as there are differences in
how males and females use their claws. A total of 730 crabs (range = 15.7–83.6 mm CW) were collected from Maine to New Jersey,
USA from May to October 1997, 2000, and 2004–2005. Claw growth, particularly crushers, was accelerated in left-handed crabs
and in males compared to right-handed crabs and females respectively. These differing growth strategies highlight the role
of sexual dimorphism in claw usage and the importance of achieving heterochely after claw injury. These results imply that
handedness should be an important factor to consider in future studies of crab morphology, behavior, and morphometrics.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
The growth rates of the morphologically similar scyllarid lobsters Ibacus peronii (Leach, 1815) and I. chacei (Brown and Holthuis, 1998) are described using data from a tag/recapture study and from tagged lobsters kept in captivity.
Within particular size classes, we found no differences in moult increments between male and female I. peronii nor between male and female I. chacei. Small individuals of both species always had larger moult increments than larger individuals. For I. peronii, females moulted more frequently than males, and smaller size classes moulted more frequently than larger size classes. Female
I. peronii therefore grew more quickly than males and reached their estimated size at sexual maturity (51 mm carapace length) after
∼2 yr. Moulting of I. peronii was seasonal, with most lobsters (96.3%) moulting between October and January. We found no differences in growth rates of
I. peronii at two locations along the east coast of Australia: Coffs Harbour in New South Wales (30°18′S; 153°08′E), and Lakes Entrance
in Victoria (37°53′S; 148°00′E). For I. chacei, we found no differences in the frequency of moulting between males and females and, because we also found no differences
in the moult increments between males and females, the growth rates of both sexes were the same.
Received: 14 August 1999 / Accepted: 20 January 2000 相似文献
3.
Understanding physiological and environmental variables that initiate sexual maturity would provide fundamental information
on life history dynamics. The aim of this study was to test the usefulness of the common circumnuclear ring (CNR), an oocytic
structure similar to the Balbiani body, which appears just prior to oocyte development as a predictor of first maturation
in Atlantic herring (Clupea harengus). The relative roles of physiology (e.g. fat) and photoperiod as triggers of maturation were also investigated. Samples were
collected in May 2008 (72°26′–73°84′N/11°26′–18°40′E) and February 2009 (56°12′–59°45′N/00°25′–03°06′W). These data suggested
that thresholds in body size may influence the decision to mature. We also found that short days (winter solstice) may be
the photoperiod trigger for a first-decision window for both Norwegian spring-spawning (NSS) and North Sea autumn-spawning
(NSAS) herring. The second-decision window for NSAS herring maturation appears to be triggered by longer days (spring equinox),
while a decreasing rate of day lengthening may trigger NSS herring maturation. So, photoperiodic cycle is a key determinate
of the timing of maturation in Atlantic herring. 相似文献
4.
Alfréd Trnka Milica Po?gayová Petr Procházka Pavol Prokop Marcel Honza 《Behavioral ecology and sociobiology》2012,66(8):1187-1194
Reproductive success of brood parasites varies considerably both among and within host species, mainly due to differences in host egg-rejection rates and survival of parasitic chicks. Here, we investigated the breeding success of the cuckoo (Cuculus canorus) in one of its major hosts, the great reed warbler (Acrocephalus arundinaceus), with respect to host social mating status. In this passerine, polygynous males provide less parental care to their young per nest than monogamous males. Consequently, their less-assisted females may fledge lower numbers of nestlings than monogamous females. This may be especially true for secondary females, which often receive limited or no paternal help with young at all. Based on these findings, we expected higher cuckoo reproductive success in nests of socially monogamous than polygynous great reed warbler males. More specifically, we predicted lower fledging success of cuckoo young in nests of secondary than primary or monogamous females. In line with the prediction, we found higher cuckoo fledging success in nests of monogamous than polygynous males, monogamous nests being more than twice as successful as secondary nests. We detected, however, only a tendency to lower cuckoo success in primary compared to monogamous nests and no differences between primary and secondary nests. Moreover, neither parasitism nor host egg-rejection rates differed among the nests of different status. Our results show, for the first time, that the social mating status of a host may influence the overall reproductive success of a brood parasite and thus should be considered in further studies. 相似文献
5.
Giant clams form a symbiosis with photosynthetic algae of the genus Symbiodinium that reside in clam mantle tissue. The allometry of symbiont photosynthetic performance was investigated as a mechanism for
the increasing percentage of giant clam carbon respiratory requirements provided by symbionts as clam size increases. Chlorophyll
fluorescence measurements of symbionts of the giant clam Tridacna maxima were measured during experiments conducted in September of 2009 using specimens 0.5–200 g tissue wet weight (3–25 cm long),
collected from waters around southern Taiwan (N 21°36′, E 120°47′) from July to August of 2009. Light-dependent decreases
in effective quantum yield (∆F/F
m′) calculated as the noontime maximum excitation pressure over PSII (Q
m), relative electron transport rates (rETR), and dark-adapted maximum quantum yield (F
v/F
m) all varied as a quadratic function of clam size. Both Q
m and rETR increased as clam size increased up to ~10–50 g then decreased as clam size increased. F
v/F
m decreased as clam size increased up to ~5–50 g then increased as clam size increased. Chlorophyll fluorescence measurements
of rETR were positively correlated with gross primary production measured during chamber incubations. Overall, symbionts of
mid-sized clams ~5–50 g exhibited the highest light-dependent decreases in effective photosynthetic efficiencies, the highest
relative electron transport rates, and the lowest maximum photosynthetic efficiencies, and symbiont photosynthetic performance
is allometric with respect to host clam size. 相似文献
6.
Dana M. Bethea Loraine Hale John K. Carlson Enric Cortés Charles A. Manire James Gelsleichter 《Marine Biology》2007,152(5):1009-1020
To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (∼29°40′N, 85°13′W),
Tampa Bay near Anclote Key (∼28°10′N, 82°42.5′W), and Florida Bay (∼24°50′N, 80°48′W) from March through September, 1998–2000.
In each area, diet was assessed by life stage (young-of-the year, juveniles, and adults) and quantified using five indices:
percent by number (%N), percent by weight (%W), frequency of occurrence (%O), index of relative importance expressed on a
percent basis (%IRI), and %IRI based on diet category (%IRIDC). Diet could not be assessed for young-of-the-year in Tampa Bay or Florida Bay owing to low sample size. Diet analysis showed
an ontogenetic shift in northwest Florida. Young-of-the-year stomachs from northwest Florida (n = 68, 1 empty) contained a mix of seagrass and crustaceans while juvenile stomachs (n = 82, 0 empty) contained a mix of crabs and seagrass and adult stomachs (n = 39, 1 empty) contained almost exclusively crabs. Crabs made up the majority of both juvenile and adult diet in Tampa Bay
(n = 79, 2 empty, and n = 88, 1 empty, respectively). Juvenile stomachs from Florida Bay (n = 72, 0 empty) contained seagrass and a mix of crustaceans while adult stomachs contained more shrimp and cephalopods (n = 82, 3 empty). Diets in northwest Florida and Tampa Bay were similar. The diet in Florida Bay was different from those in
the other two areas, consisting of fewer crabs and more cephalopods and lobsters. Plant material was found in large quantities
in all stomachs examined from all locations (>15 %IRIDC in 6 of the 7 life stage-area combinations, >30 %IRIDC in 4 of the 7 combinations, and 62 %IRIDC in young-of-the-year diet in northwest Florida). Using species- and area-specific inputs, a bioenergetic model was constructed
to estimate daily ration. Models were constructed under two scenarios: assuming plant material was and was not part of the
diet. Overall, daily ration was significantly different by sex, life stage, and region. The bioenergetic model predicted increasing
daily ration with decreasing latitude and decreasing daily ration with ontogeny regardless of the inclusion or exclusion of
plant material. These results provide evidence that bonnetheads continuously exposed to warmer temperatures have elevated
metabolism and require additional energy consumption to maintain growth and reproduction.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Sarcophyton elegans is a common symbiotic (zooxanthellate) octocoral species in the shallow waters of the Great Barrier Reef (GBR). Study of
a population at Lizard Island (14°40′S, 145°28′E) on the GBR from October 1991 to January 1994 revealed that, as is typical
of tropical alcyonarian corals, S. elegans is a gonochoric broadcast spawner with a 1:1 sex ratio. Sexual reproduction was closely correlated with colony size, with
first reproduction at 13-cm basal stalk circumference for females and 12 cm for males. Oogenesis took 19–24 months, with a
new cycle commencing every year, and spermatogenesis took 10–12 months. The majority of gametes were released during the annual
austral mass coral spawning event after the full moon in November, but gametes were also released after the full moon in each
month between August and February. All autozooid polyps participated in reproduction, but those at the outer edge of a colony
released their gametes first. During subsequent months, the polyps closer to the center of the colony released their gametes.
This is a novel strategy of gamete release, reported here for the first time, which accommodates the demands of feeding and
reproduction in a different way than other corals where individual polyps have separate feeding or reproductive roles. Colonies
upstream in the prevailing current spawned up to 1 month earlier than those downstream and ceased 1 month earlier. The mechanism
controlling this spatial differentiation in spawning time, repeatedly observed over three seasons, is unknown. Sarcophyton elegans appears to have a dual strategy of providing protection for its gametes by releasing most of them concurrently with the single,
annual mass spawning of a large number of cnidarians, while also hedging its bets by individual colonies spawning a fraction
of their gametes over an extended period of 6 months. 相似文献
8.
Hawksbill sea turtles (Eretmochelys imbricata) nesting in Barbados (Needham’s Point, 13° 04′ 41.33′′ N, 59° 36′ 32.69′′W) were outfitted with GPS dataloggers over three
breeding seasons (2008–2010) to track movement during inter-nesting intervals. Most females established spatially restricted
resident areas up current and within 7 km of the nesting beach where they spent the majority of the inter-nesting interval.
Females nesting earlier in the season settled on shallower sites. Only experienced remigrant turtles occupied the most distant
resident areas. Females tracked for multiple inter-nesting intervals exhibited site fidelity, but the area contracted and
the activity of females decreased with each successive interval. Hawksbills may trade off site characteristics with distance
from the nesting beach and reduce activity over the course of the breeding season to optimise energy reserves during inter-nesting
intervals. 相似文献
9.
The extent to which male birds in polygynous species with biparental care assist in nestling feeding often varies considerably
between nests of different mating status. Both how much polygynous males assist and how they divide their effort between nests
may have a profound effect on the evolution of mating systems. In this study we investigated how males in the facultatively
polygynous European starling Sturnus vulgaris invested in their different nests. The amount of male assistance affected the quality of the offspring. Polygynous males
invested as much as monogamous males, but divided their effort asymmetrically between nests, predominantly feeding nestlings
of first-mated (primary) females. Although females partly compensated for loss of male assistance, total feeding frequency
was lower at primary females’ nests than at monogamous females nests. Secondary females received even less assistance with
nestling rearing, and the extent to which males assisted decreased with the length of the interval between the hatching of
the primary and secondary clutches. These results are contrasted with those from a Belgian populations of starlings with a
much more protracted breeding season and thus greater opportunities for males to attract additional mates during the nestling
rearing period. The results show that both the “defence of male parental investment model” and the “asynchronous settlement
model” have explanatory power, but that their validity depends on the potential length of the breeding season.
Received: 21 July 1995/Accepted after revision: 13 July 1996 相似文献
10.
Sophie Beltran Frank Cézilly Jérôme Boissier 《Behavioral ecology and sociobiology》2009,63(9):1363-1368
“Divorce” (mate switching) rate is known to vary largely both between and within socially monogamous species. Although the
adult sex ratio can have an important influence on mating patterns, very few studies have investigated the influence of sex
ratio on divorce rate in monogamous species, and even less so from an experimental point of view. In addition, most studies
on the causes and consequences of divorce have been performed on vertebrate species, whereas data for invertebrate monogamous
species remain scarce. Schistosoma mansoni is a monogamous endoparasite with a complex life cycle characterized by asexual reproduction in the intermediate host and
sexual reproduction in the definitive host. In the wild, populations of S. mansoni inside their definitive hosts are characterized by a male-biased sex ratio. We studied the influence of experimentally varying
the adult sex ratio on divorce rate in S mansoni, using controlled infections of hosts with clonal populations. The more male-biased the sex ratio was, the more the divorce
rate increased, whereas no such effect was observed under a female-biased sex ratio. In this study and for the first time,
we showed, by handling the sex ratio, that the divorce rate increases in adult male-biased sex ratio conditions in a monogamous
species. 相似文献
11.
Field experiments were conducted from dusk to dawn off St. John (18° 18′ 59.32″ N, 64° 43′ 24.5″ W) and Guana Island (18°
28″ 28.31″ N, 64° 34′ 30.83″ W), Virgin Islands from June through August 2008-2010 to assess the sensory cues used by the
nocturnal/crepuscular fish-parasitic gnathiid isopod, Gnathia marleyi, to locate fish hosts. Experimental traps providing both visual and olfactory cues from live French grunts (Haemulon flavioliniatum) attracted significantly more gnathiids than traps providing only visual cues or control traps (empty or with a rock), which
were not significantly different from each other. In another experiment, traps providing both cues and only olfactory cues
attracted significantly more gnathiids than empty control traps, but were not significantly different from each other. Our
findings suggest that during nocturnal and crepuscular periods, visual cues provided by resting or slow-moving fish are not
alone sufficient to attract gnathiids, while olfactory cues alone are. The traps designed for this study offer a new method
of sampling free-living gnathiid isopods. 相似文献
12.
Joseph M. O’Malley 《Marine Biology》2011,158(8):1887-1901
Scaly slipper lobster (Scyllarides squammosus) population ecology was examined using tag/recapture information at Necker Island (23°30′N; 164°35′W), Gardner Pinnacles
(25°00′N; 168°50′W), Maro Reef (25°30′N; 170°45′W), and Laysan Island (25°48′N; 171°45′W) in the Northwestern Hawaiian Islands
(NWHI) USA from 2002 to 2008. Although many aspects of S. squammosus life history and population dynamics were similar to those of other scyllarids, somatic growth differed from its congers.
Scyllarides squammosus growth abruptly declined at maturity and, because of this, growth at length was better described using the Schnute as opposed
to the more commonly von Bertalanffy growth model. Growth varied among locations, and survival varied among years; thereby
being the first documentation of variability in the life history of a scyllarid. This study has expanded knowledge of scyllarid
biology and documented that spatiotemporal variability in biological characteristics must be considered to understand and
describe the population ecology of this species and probably of other scyllarids. 相似文献
13.
14.
Marine sponges harbor dense and highly diverse bacterial communities, and some percentage of the microflora appears to be
specialized for the sponge habitat. Bacterial diversity was examined in Chondrilla nucula Schmidt to test the hypothesis that some subset of sponge symbiont communities is highly similar regardless of the species
of host or habitat requirements of the host. C. nucula was collected from a mangrove channel on Lower Matcumbe Key in the Florida Keys (25°53′N; 80°42′W) in August 1999. Domain-specific
universal bacterial primers were used to amplify the 16S rDNA gene from genomic DNA that had been extracted from sponges and
the surrounding water. An RFLP technique was used to assess diversity of sponge-associated and environmental bacterial communities.
The clone library from C. nucula contained 21 operational taxonomic units (OTUs). None of the 53 OTUs from adjacent water samples were found in the C. nucula library indicating that a distinct community was present in the sponge. Sequence analysis indicated that C. nucula harbors a microbial community as diverse as the microbes from other sponges in different habitats around the world. Phylogenetic
analysis placed several C. nucula clones in clades dominated by bacteria that appear to be sponge specialists (e.g., Acidobacteria, Bacteroidetes, and Cyanobacteria).
Proportional representation of major bacterial taxonomic groups represented in symbiont communities was compared as a function
of geographic location of sponge hosts. This study supports the hypothesis that sponges from different oceans existing in
dissimilar habitats harbor closely related bacteria that are distinct from other bacterial lineages and appear specialized
for residing within sponges. 相似文献
15.
Parental care may be costly to parents because it decreases resources allocated to self-maintenance and may thus reduce survival
and future reproductive success. An inter-sexual conflict may exist in animals with obligatory bi-parental care, such as birds
of prey, in which females incubate and brood, whereas males provision food for their families. We analysed 29 years of data
(1981–2009) from a study population of Tengmalm’s owls Aegolius funereus in western Finland to examine the occurrence and timing of brood desertion and sequential polyandry, and recorded a total
of 1,123 monogamous and 12 polyandrous females. These data were supplemented with the 29-year nationwide Finnish ringing data,
which included 11,590 monogamous and 20 polyandrous females. The 12 polyandrous females started egg-laying in their two nests
at intervals of 54–68 days (mean 60 days), thus deserting their first broods when the age of oldest young averaged 21 days.
Thirty-two polyandrous females re-mated and raised a second brood at a median distance of 4.5 km (range 1–196 km). These females
produced 79% more eggs, 93% more hatchlings and 73% more fledglings than did females that laid simultaneously but remained
monogamous. Our results show that not only males, but also females of altricial species with bi-parental care can increase
their fitness by deserting their first brood when it will be cared for by the males. Earlier studies have shown that male
owls can increase their lifetime reproductive success by simultaneous polygyny, and we suggest that an inter-sexual “tug-of-war”
over bi-parental care exists in Tengmalm’s owls. 相似文献
16.
Two potential mechanisms for reducing the level of inbreeding, sex-biased dispersal and kin avoidance, were examined in the
Australian sleepy lizard, Tiliqua rugosa. The home range centres, and the genotypes at four polymorphic microsatellite DNA loci were determined for adult lizards
in a 70-ha study area near Mount Mary, South Australia. From estimates of genetic relatedness, females were as closely related
to other females as they were to males, both within the whole study area, and within home ranges. Similarly, males were as
closely related to other males as they were to females. This suggests that dispersal in the population is not sex-biased.
Sleepy lizards form monogamous pairs during the spring. Partners were less closely related to each other than to other potential
partners in the home range area. This suggests active choice of unrelated partners. The mechanism for recognising related
from unrelated individuals is unknown, but the behaviour could reduce inbreeding.
Received: 7 November 1998 / Accepted: 30 May 1999 相似文献
17.
Brood sex ratio is dependent on female mating status in polygynous great reed warblers 总被引:2,自引:0,他引:2
Isao Nishiumi 《Behavioral ecology and sociobiology》1998,44(1):9-14
Females capable of adjusting the sex ratio of their offspring should be more fit than females lacking such an ability. In
polygynous birds where breeding success in males is more strongly influenced by body size and/or attractiveness than in females,
females might produce more sons when predicting good conditions or when mating with attractive males. Polygynous great reed
warbler, Acrocephalusarundinaceus, males direct most of their feeding effort to the primary (first-hatching) nest and in these nests increase their feeding
effort in relation to the brood sex ratio (proportion of sons). Therefore, with the expectation of well-nourished sons, we
would predict that females which start breeding first within harems might produce more sons than those which start breeding
later, and in anticipation of sons with good genes, that females mated to polygynous males might produce more sons than females
mated to monogamous males. I took blood samples from hatchlings and determined the sex using DNA markers. The sex ratio of
primary (monogamous and polygynous primary) broods is more male-biased (mean 0.58 males, n = 50) than that of secondary (polygynous secondary and tertiary) broods (mean 0.46, n = 25). Moreover, in the secondary broods with the largest clutch (five eggs), in which offspring are most likely to suffer
food shortage, the sex ratio was distinctively female biased (mean 0.33, n = 10). In the primary broods, sex ratio was correlated to harem size. The results suggest that great reed warbler females
modify the brood sex ratio to produce both well-nourished sons and sons with good genes, but the former effect is probably
stronger than the latter factor.
Received: 11 March 1998 / Accepted after revision: 23 May 1998 相似文献
18.
Domoic acid in benthic flatfish on the continental shelf of Monterey Bay,California, USA 总被引:1,自引:0,他引:1
Within Monterey Bay, California, USA, the food web transfer of domoic acid (DA), a neurotoxin produced by diatoms of the genus
Pseudo-nitzschia, has led to major mortality events of marine mammals and birds. Less visible, and less well known, is whether invertebrates
and fish associated with the benthos are also affected by blooms of DA-producing Pseudo-nitzschia spp. This study examines the presence of DA in benthic flatfish offshore of Davenport, California, (37°0′36″N, 122°13′12″W)
and within Monterey Bay, California (36°45′0″N, 122°1′48″W), including species that feed primarily in the sediment (benthic-feeding)
and species that feed primarily in the water column (benthopelagic-feeding). Flatfish caught between 10 December 2002 and
17 November 2003 at depths of 30–180 m had concentrations of DA in the viscera ranging from 3 to 26 μg DA g−1 of viscera. Although the DA values reported are relatively low, benthic-feeding flatfish were frequently contaminated with
DA, especially as compared with the frequency of contamination of flatfish species that feed in the water column. Furthermore,
on days in which both benthic-feeding and benthopelagic-feeding flatfish were collected, the former had significantly higher
concentrations of DA in the viscera. Curlfin turbot, Pleuronicthys decurrens, the flatfish with both the highest level and frequency of DA contamination, are reported to feed exclusively on polychaetes,
suggesting that these invertebrates may be an important vector of the toxin in benthic communities and may pose a risk to
other benthic-feeding organisms.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
20.
Adults of motile intertidal invertebrates are able to seek shelter to avoid environmental stress associated with low tides,
but embryos within egg masses are effectively sessile for the duration of their encapsulation. Gastropod egg masses from 34
taxa on two rocky shores in SE Australia (34°37′08″S, 150°92′03″E and 34°35′45″S, 150°53′20″E) were surveyed over 2 years
(June 2002–May 2004) to test the hypothesis that eggs are deposited in patterns that minimize exposure to environmental stress.
Egg masses were expected to be predominantly deposited in shaded habitats not prone to environmental extremes. It was also
anticipated that the deposition of egg masses in habitats exposed to UVR, desiccation, and/or extremes in temperature would
occur when exposure to these abiotic factors was minimized. Among the taxa investigated, only four species spawned in full
sun (Bembicium nanum, Nerita morio, Siphonaria zelandica and S. denticulata). Summer had the highest UVR index, water temperature, and air temperature as well as the lowest daytime tides. Univariate
and multivariate analyses confirmed that egg mass abundance was highest during summer, with no change in egg mass size. This
study shows that those species depositing egg masses on the surfaces of rock platforms do not adjust the seasonal timing or
macrohabitat location of their spawning to avoid physiologically stressful conditions, particularly UVR. Alternate reasons
for the evolution of egg mass deposition behavior in apparently sub-optimal habitats are discussed, and it is almost certainly
the complex interplay of a variety of highly species-specific factors that is responsible for the patterns observed. 相似文献