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71.
Hoplolaimus concaudajuvencus n. sp., of the genus Hoplolaimus Daday, 1905, characterized by larval heteromorphism, is described and illustrated as recovered from ryegrass/bermudagrass golf green turf in Florida. Females and males are closely related to H. galeatus (Cobb, 1913) Thorne, 1935, but have longer stylets with more definitely tulip-shaped stylet knobs which anteriorly tend to close upon the stylet shaft more than in H. galeatus. First and second-stage larvae have a conically-pointed tail unlike any known species of the genus. Subsequent stages, including females, have rounded tails essentially similar to other species of the genus and males possess the typical hopolaimid tail and bursa. The first molt was found to occur within the egg. 相似文献
72.
Tatsuro Kono 《Population Ecology》1953,2(1):85-94
Contributions from the Entomological Laboratory, Kyoto University, No. 230. 相似文献
73.
Giovana Duarte Viana Rodrigues João Paulo Felix Augusto de Almeida Tamí Mott 《Studies on Neotropical Fauna and Environment》2017,52(3):204-215
Herein, we provide external and internal morphological data of Scinax skuki tadpoles from its type locality. The benthic tadpole of S. skuki has eyes and nostrils positioned dorsally, vent tube dextral and reaching the free margin of the ventral fin, oral disk ventral with posterior margin concave when partially closed, labial tooth row formula 2/3, and the presence of nonpigmented spurs behind the lower jaw. These characters, together with the absence of a tectum parietale, and the shapes of the pars articularis quadrati and suprarostral, are useful for species identification and may be informative for systematic purposes. 相似文献
74.
Although mycosporine-like amino acids (MAAs) have been extensively investigated in reef-building corals, the sources of these
MAAs and the process of their interconversion remain a topic of interest. Here we examined ontogenetic change in the abundance
of MAAs in planula larvae of the spawning scleractinian coral Goniastrea retiformis in the absence of zooxanthellae and other dietary input. In order to examine the potential contribution of prokaryotes in
the synthesis of MAAs in animal tissue, one group of larvae were treated with the antibiotic rifampicin. High concentrations
of MAAs (mycosporine-glycine, shinorine, palythinol, asterina-330), were present in the asymbiotic eggs and adults; however,
no MAAs were present in the endosymbiotic zooxanthellae. We documented a steady decline in the total MAA concentrations through
time in larvae treated with rifampicin; however, in the absence of antibiotic there was a significant increase in the concentration
of MAAs, driven by a sharp increase in the abundance of shinorine and palythinol between day 3 and 7. Our results suggest
that MAA synthesis and conversion in G. retiformis larvae occurred in the absence of symbiotic zooxanthellae, and indicate a possible contribution of prokaryotes associated
with the animal tissue to these processes. 相似文献
75.
Adam M. Reitzel Larry R. McEdward 《Journal of experimental marine biology and ecology》2005,317(2):189-201
Planktotrophic invertebrate larvae have two dissociable stages during development, a facultative feeding period, whose length is determined by the amount of maternal provisioning in the egg, and an obligate feeding period, whose length is determined by the quantity of exogenous energy needed to reach metamorphic competence. Here we set out to experimentally test the impact of feeding during the facultative feeding period at two food concentrations (limiting and nonlimiting) on larval development time and juvenile quality. We used two closely related subtropical sand dollar species that differ in the quantity of maternal investment for these comparisons: Leodia sexiesperforata (large egg, long facultative feeding period) and Mellita tenuis (small egg, short facultative feeding period). We found that feeding during the facultative period accelerates development to metamorphosis only in M. tenuis and only at the high food ration. Feeding during the facultative feeding period had no effect on development time for M. tenuis at a food limiting concentration and for L. sexiesperforata at either food concentration. Furthermore, we found feeding during the facultative period to significantly increase quantity of carbohydrates and lipids at metamorphosis only for M. tenuis in nonlimiting food concentration. Thus, our data reveal a two-fold benefit of the facultative feeding period for a poorly provisioned species under high food conditions but little effect on a well-provisioned species. We discuss our results in reference to McEdward's [McEdward, L.R., 1997. Reproductive strategies of marine benthic invertebrates revisited: facultative feeding by planktotrophic larvae. Am. Nat. 150, 48-72] facultative feeding model. 相似文献
76.
The complete larval development (four zoeae and one megalopa) of Clibanarius aequabilis and C. erythropus, reared under laboratory conditions, is described and illustrated. The larval stages of the two northeastern Atlantic Clibanarius species cannot be easily differentiated. Their morphological characters are compared with those of other known Clibanarius larvae. The genus Clibanarius is very homogeneous with respect to larval characters. All Clibanarius zoeae display a broad and blunt rostrum, smooth abdominal segments and an antennal scale without a terminal spine. Beyond
the second zoeal stage, the fourth telson process is present as a fused spine, and the uropods are biramous. In the fourth
larval stage all species display a mandibular palp. The Clibanarius megalopa presents weakly developed or no ocular scales, symmetrical chelipeds, apically curved corneous dactylus in the second
and third pereiopods, and 5–11 setae on the posterior margin of the telson. Apart from the number of zoeal stages, Clibanarius species may be separated, beyond the second zoeal stage, by the telson formula and the morphology of the fourth telson process. 相似文献
77.
狭额绒螯蟹的幼体发育 总被引:1,自引:0,他引:1
在水温18—20℃、盐度18‰—20‰、光照度200~600Ix的条件下,狭颚绒鳌蟹幼体发育经5个溞状幼体和1个大眼幼体期。从幼体出膜到大眼幼体出现历时15d、到仔蟹出现需23d。狭颚绒鳌蟹和中华绒鳌蟹的第一期溞状幼体可从第2触角的外肢、腹部侧刺数加以区别;两大眼幼体可从额角形状、第2—4胸足指节、腹肢外肢刚毛数及尾节刚毛着生情况进行区分。 相似文献
78.
Connectivity and resilience of coral reef metapopulations in marine protected areas: matching empirical efforts to predictive needs 总被引:2,自引:1,他引:1
Botsford LW White JW Coffroth MA Paris CB Planes S Shearer TL Thorrold SR Jones GP 《Coral reefs (Online)》2009,28(2):327-337
Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population
models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing
of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal
is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix
containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged
among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale
of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal
influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical
and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report
current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local
retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of
biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their
sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress
in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers
will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population
modelers need to track and assimilate evolving empirical results. 相似文献
79.
The dispersal of gametes and larvae plays a key role in the population dynamics of sessile marine invertebrates. Species with
internal fertilisation are often associated with very localised larval dispersal, which may cause small-scale patterns of
neutral genetic variation. This study on the brooding coral Seriatopora hystrix from the Red Sea focused on the smallest possible scale: Two S. hystrix stands (~100 colonies each) near Dahab were completely sampled, mapped and analysed at five microsatellite markers. The sexual
mode of reproduction, the likely occurrence of selfing and the level of immigration were in agreement with previous studies
on this species. Contrary to previous findings, both stands were in Hardy–Weinberg proportions. Also, no evidence for spatially
restricted larval dispersal within the sampled areas was found. Differences between this and previous studies on S. hystrix could reflect variation in life history or varying environmental conditions, which opens intriguing questions for future
research. 相似文献
80.
湘江鳡仔稚鱼个体和耳石生长发育研究 总被引:2,自引:0,他引:2
2008 年6 月至7 月间于鳡(Elopichthys bambusa Richardson)的主要繁殖季节在湘江采集鳡仔稚鱼共370尾, 耳石分析表明这些仔稚鱼日龄在4-25d 间, 推算孵化日期为5 月27 日至6 月22 日。仔鱼前弯曲期向弯曲期转化时间为第6 日龄, 弯曲期向后弯曲期转化为第10 日龄, 后弯曲期向稚鱼期转化为15.5 日龄。体长生长和耳石生长均在进入后弯曲期后(12-13 日龄)出现1 个节点: 节点后体长生长速度是节点前的5 倍,节点后耳石生长速度是节点前的2 倍。早期生活史不同阶段鳡微耳石形态显著改变: 前弯曲期耳石为圆形;弯曲期耳石前后轴的生长速度明显超过背腹轴生长, 耳石也变为椭圆形; 后弯曲期耳石进一步延长, 耳石后端形成略尖的突起, 耳石呈梨形; 进入稚鱼期后, 耳石后突起变得较为平滑, 耳石形状呈贝形。耳石半径和体长的关系在后弯曲期阶段出现节点, 节点前后呈不同的直线关系。
相似文献