scholarly journals The life cycle of a desert spider inferred from observed size frequency distribution

2012 ◽  
Vol 28 (2) ◽  
Author(s):  
Irma Gisela Nieto-Castañeda ◽  
Saías Hazarmabeth Salgadougarte ◽  
María Luisa Jiménez-Jiménez
Keyword(s):  
Life Cycle ◽  
Body Size ◽  
Size Structure ◽  
Length Distribution ◽  
The Body ◽  
Statistical Tool ◽  
Size Frequency Distribution ◽  
Mating Period ◽  
Frequency Distributions ◽  
Size Groups

We studied the life cycle of the spider Syspira tigrina (Araneae: Miturgidae) by indirect methods. This species is endemic to the North American deserts and locally abundant; nevertheless, information on its biology is scarce. We did monthly collections for over a year at La Paz, Baja California Sur, Mexico. We found that adult spiders were more abundant between August and November 2005 and had low abundance or were absent the remainder of the year while juveniles were present all year. To estimate changing body size structure of the population we analyzed juvenile tibia I length distribution (TIL) (as indicator of the body size) of each monthly sample by means of Kernel Density Estimators (KDEs). We found 35 TIL juveniles size groups (Gaussian components). The smallest juveniles were more abundant between October 2005 and January 2006 and the biggest were more abundant twice during the hottest months. We hypothesize that mating period is between August and October 2005 and the main recruitment period from November 2005 and January 2006. However we found evidenceof continuous recruitment through the year, suggesting that although there is a peak of reproduction in November, the females oviposit almost all year. Also there is evidence of juveniles’ growth pattern from January to July 2006. The use of KDEs with histograms is a very good statistical tool to delimit size groups with mixed frequency distributions that otherwise might be difficult. This tool should be useful to test any hypothesis related with the body size structure of a population or community.

scholarly journals Linking population size structure, heat stress and bleaching responses in a subtropical endemic coral

Coral Reefs ◽  
2021 ◽  
Author(s):  
Liam Lachs ◽  
Brigitte Sommer ◽  
James Cant ◽  
Jessica M. Hodge ◽  
Hamish A. Malcolm ◽  
...  
Keyword(s):  
Heat Stress ◽  
Size Structure ◽  
Temporal Trends ◽  
Early Recovery ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Community Organisation ◽  
Size Frequency ◽  
Eastern Australia

AbstractAnthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.

scholarly journals The developmental variations of the sagitta otolith in the young and mature male of a hermaphrodite polynemidae fish, Eleutheronema tetradactylum (Shaw, 1804)

2021 ◽  
Vol 61 ◽  
pp. e20216178
Author(s):  
Soumen Roy ◽  
Itika Bardhan
Keyword(s):  
Body Size ◽  
Fork Length ◽  
The Body ◽  
Size Groups ◽  
Protandrous Hermaphrodite ◽  
Ultrastructural Characteristics ◽  
Developmental Variations ◽  
The One ◽  
First Time ◽  
One Way Anova

The Eleutheronema tetradactylum is a protandrous, hermaphrodite, marine perciformes fish. The body length of this fish acts as an important diagnostic marker for male and female discrimination. The present study describes for the first time the ultrastructural characteristics on the medial surface of the sagitta otolith in different body size groups of males of E. tetradactylum (Polynemidae: Perciformes) using scanning electron microscopy. The sagitta is a spindle-shaped structure that includes a well-developed rostrum and a poorly developed antirostrum. The sulcus is ostio-pseudocaudal type, almost straight and devoid of the collum. The ostium is a well-developed, vase-shaped structure. The cauda includes the colliculum and a well-developed caudal bulb with several distinct growth stripes. The length of the caudal bulb is significantly correlated to the growth of the body size of the fish. The excisura major is indistinct and the excisura minor is absent. The cristae are distinct on both sides of the sulcus. The one-way ANOVA test revealed that the development of several sagitta features shows significant differences in various body size groups of E. tetradactylum. The growth of the sagitta length is more closely related to the fork length than the sagitta width. Therefore, the sagitta length and the caudal bulb length can be used as important predictors to evaluate the fish size. The cauda region of the sagitta in E. tetradactylum is unique as well as more decorative than those of another Polynemidae fish and other hermaphrodite, marine perciformes fishes. The sagitta characteristics of E. tetradactylum might be advantageous in the identification of the sex and the taxonomy of the hermaphrodite fish species.

scholarly journals Evidence for benthic body size miniaturization in the deep sea

2006 ◽  
Vol 86 (6) ◽  
pp. 1339-1345 ◽  
Author(s):  
Janne I. Kaariainen ◽  
Brian J. Bett
Keyword(s):  
Body Size ◽  
Deep Sea ◽  
Size Structure ◽  
Size Class ◽  
The Body ◽  
Significant Shift ◽  
Individual Biomass ◽  
Wet Weight ◽  
Accumulation Curves ◽  
Average Individual

The benthic body size miniaturization hypothesis states that deep-sea communities are dominated by organisms of smaller body size, although some field studies have produced contradictory results. Using appropriate sample sets, this study tests this hypothesis by contrasting the benthic communities of the Fladen Ground (North Sea, 150 m) and the Faroe–Shetland Channel (1600 m). Samples were collected for large (500 μm) and small macrofauna (250–355 μm), meiofauna (45 μm) as well as an intermediate sized ‘mesofauna’ (180 μm) to ensure comprehensive coverage of the full meio- and macro-faunal body size-range. The body size structure of the benthos was compared using two methods. The more widely used average individual biomass method involves dividing the total sample biomass by sample abundance. Additionally, body size accumulation curves were constructed by assigning all specimens into a logarithmic size-class and then plotting the cumulative percentage of individuals present in each size-class. The results seem to support the hypothesis that the deep-sea environment is a small organism habitat. Although these findings only represent two locations, the overall body size accumulation curves clearly display a statistically significant shift towards smaller body sizes at the deeper site. The magnitude of the effect is appreciable with median metazoan body size reducing from 14.3 μg wet weight in the Fladen Ground to 3.8 μg wet weight in the Faroe–Shetland Channel. The average individual biomass measurements are shown to be of limited value and can lead to potentially misleading conclusions if the underlying size structure is not analysed in detail.

Effect of stingray (Hemitrygon akajei) foraging on a ghost shrimp population (Nihonotrypaea harmandi) on an intertidal sandflat, western Kyushu, Japan

2020 ◽  
Vol 71 (9) ◽  
pp. 1128
Author(s):  
Akio Tamaki ◽  
Kazuyuki Harada ◽  
Yoshinobu Sogawa ◽  
Seiji Takeuchi
Keyword(s):  
Spring Tide ◽  
The Body ◽  
Gut Contents ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Size Frequency ◽  
Intertidal Sandflat ◽  
Shrimp Density ◽  
Feeding Bout ◽  
Shrimp Population

Callianassid shrimp residing in deep burrows have large bioturbating effects on marine soft-bottom communities. A few predators that excavate deep pits could have substantial effects on shrimp populations, as well as knock-on effects. Processes and consequences of such effects on shrimp populations are poorly understood. On a 300-m-wide intertidal sandflat area between tide marks in western Kyushu between 1989 and 1994, shrimp population densities were stable, reaching >1300individualsm–2. Dasyatid stingray feeding pits reaching depths up to 20cm occurred abruptly in large numbers in 1994, after which shrimp densities decreased yearly to hundreds of individuals per square metre in 2001. The densities of ray feeding pits formed per day were monitored every or every other spring tide between 2000 and 2001. Schools of rays were enclosed during submerged times and their body sizes recorded alive to determine size-frequency distribution. The body-size frequency distributions of shrimp were compared among the gut contents of several rays, ray feeding pits and intact sandflat. Reductions in the shrimp density per ray feeding bout compared with the density on the intact sandflat were recorded. A model of daily predation at different seasonal rates was used to simulate the yearly change in shrimp density. The result was consistent with the actual change.

The Slippery Slope: Towards an Understanding of the Body Size Frequency Distribution

Oikos ◽  
1997 ◽  
Vol 78 (1) ◽  
pp. 195 ◽  
Author(s):  
Natasha Loder ◽  
Tim M. Blackburn ◽  
Kevin J. Gaston
Keyword(s):  
Body Size ◽  
Frequency Distribution ◽  
The Body ◽  
Slippery Slope ◽  
Size Frequency Distribution ◽  
Size Frequency

scholarly journals Body Size and Behaviour Traits of Dogs in Czech Households

2009 ◽  
Vol 78 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Eva Baranyiová ◽  
Antonín Holub ◽  
Mojmír Tyrlík
Keyword(s):  
Body Size ◽  
Body Mass ◽  
The Body ◽  
Medium Size ◽  
Rural Environments ◽  
Size Groups ◽  
Working Dogs ◽  
Average Body Mass ◽  
Household Members ◽  
Giant Size

The objective of this study was to analyse the effect of body size of dogs on their coexistence with humans in Czech households. For this purpose we used questionnaire data on 246 dogs indicating the breed. The dogs were divided into five body size groups, i.e. toy (T, up to 5 kg body mass, n = 32), small (S, 5 - 10 kg body mass, n = 52), medium size (M, 10 - 17 kg body mass, n = 39), large (L, 17 - 33 kg body mass, n = 70), giant (G, over 33 kg body mass, n = 53). The largest dogs surpassed the body mass of the smallest dogs at least seven times, and giant dogs weighed at least one half and toy dogs less than one tenth of the average body mass of people in the Czech human population. Despite this the majority of the studied traits regardless of body mass of the dogs showed no significant differences. In the vast majority of Czech households all dogs were considered household members, taken on travels or vacations, photographed and their birthdays were celebrated. Aggressiveness of the dogs did not correlate with their body size. Among the 84 traits of the behaviour of dogs and their owners, which were analysed, only 23, i.e. 27.4% traits were significantly related to their body mass. Larger and heavier dogs were more frequently kept in houses with yards and gardens, in rural environments. Toy and small dogs prevailed in urbanised environments, in apartments. They were allowed to use furniture, sleep in beds of household members. Moreover, toy dogs predominated in one-person households. Large dogs were more often trained, sometimes by professional trainers, obeyed commands better and were more often described as obedient. They were considered not only as companions but also as working dogs. Giant size dogs were also more often trained to be protective. These data show that the differences in the body size of dogs modified their co-existence with humans only to a limited extent.

The body-size structure of macrobenthos changes predictably along gradients of hydrodynamic stress and organic enrichment

2015 ◽  
Vol 162 (3) ◽  
pp. 675-685 ◽  
Author(s):  
Serena Donadi ◽  
Britas Klemens Eriksson ◽  
Karsten Alexander Lettmann ◽  
Dorothee Hodapp ◽  
Jörg-Olaf Wolff ◽  
...  
Keyword(s):  
Body Size ◽  
Size Structure ◽  
The Body ◽  
Organic Enrichment ◽  
Hydrodynamic Stress

scholarly journals Macroscale patterns of oceanic zooplankton composition and size structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoela C. Brandão ◽  
Fabio Benedetti ◽  
Séverine Martini ◽  
Yawouvi Dodji Soviadan ◽  
Jean-Olivier Irisson ◽  
...  
Keyword(s):  
Body Size ◽  
Community Composition ◽  
Climate Models ◽  
Size Structure ◽  
Fish Larvae ◽  
The Body ◽  
Community Level ◽  
Feeding Strategies ◽  
Size Spectrum ◽  
Zooplankton Abundance

AbstractOcean plankton comprise organisms from viruses to fish larvae that are fundamental to ecosystem functioning and the provision of marine services such as fisheries and CO2 sequestration. The latter services are partly governed by variations in plankton community composition and the expression of traits such as body size at community-level. While community assembly has been thoroughly studied for the smaller end of the plankton size spectrum, the larger end comprises ectotherms that are often studied at the species, or group-level, rather than as communities. The body size of marine ectotherms decreases with temperature, but controls on community-level traits remain elusive, hindering the predictability of marine services provision. Here, we leverage Tara Oceans datasets to determine how zooplankton community composition and size structure varies with latitude, temperature and productivity-related covariates in the global surface ocean. Zooplankton abundance and median size decreased towards warmer and less productive environments, as a result of changes in copepod composition. However, some clades displayed the opposite relationships, which may be ascribed to alternative feeding strategies. Given that climate models predict increasingly warmed and stratified oceans, our findings suggest that zooplankton communities will shift towards smaller organisms which might weaken their contribution to the biological carbon pump.

scholarly journals Geographical patterns in the body-size structure of European lake fish assemblages along abiotic and biotic gradients

2014 ◽  
Vol 41 (12) ◽  
pp. 2221-2233 ◽  
Author(s):  
Matthias Emmrich ◽  
Stéphanie Pédron ◽  
Sandra Brucet ◽  
Ian J. Winfield ◽  
Erik Jeppesen ◽  
...  
Keyword(s):  
Body Size ◽  
Fish Assemblages ◽  
Size Structure ◽  
The Body ◽  
Geographical Patterns ◽  
Lake Fish

scholarly journals Testing size–frequency distributions as a method of ontogenetic aging: a life-history assessment of hadrosaurid dinosaurs from the Dinosaur Park Formation of Alberta, Canada, with implications for hadrosaurid paleoecology

Paleobiology ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 379-404
Author(s):  
Mateusz Wosik ◽  
Kentaro Chiba ◽  
François Therrien ◽  
David C. Evans
Keyword(s):  
Life History ◽  
Body Size ◽  
Frequency Distribution ◽  
Growth Rates ◽  
Long Bone ◽  
Size Frequency Distribution ◽  
Frequency Distributions ◽  
Size Frequency ◽  
Combining Data ◽  
Dinosaur Park Formation

AbstractHadrosaurid dinosaurs, the dominant large-bodied terrestrial herbivores in most Laurasian Late Cretaceous ecosystems, have an exceptional fossil record consisting of many species known from partial ontogenetic series, making them an ideal clade with which to conduct life-history studies. Previous research considered the Dinosaur Park Formation (DPF) of Alberta as an attritional, or time-averaged, sample and interpreted size–frequency distribution of long bones collected from the DPF with three size classes to suggest that hadrosaurids from the DPF attained near-asymptotic body size in under 3 years. This conflicted with previously published osteohistological estimates of 6+ years for penecontemporaneous hadrosaurids from the Two Medicine Formation (TMF) of Montana, suggesting either extreme variation in hadrosaurid growth rates or that size–frequency distributions and/or osteohistology and growth modeling inaccurately estimate ontogenetic age.We tested the validity of the previously proposed size–age relationship of hadrosaurids from the DPF by significantly increasing sample size and combining data from size–frequency distributions and osteohistology across multiple long-bone elements. The newly constructed size–frequency distributions typically reveal four relatively distinct size–frequency peaks that, when integrated with the osteohistological data, aligned with growth marks. The yearling size class was heavily underrepresented in the size–frequency distribution. If not due to preservation, this suggests that either juvenile (<2 years of age) hadrosaurids from the DPF had increased survivorship following an initially high nestling mortality rate or that yearlings were segregated from adults. A growth-curve analysis revealed asymptotic body size was attained in approximately 7 years, which is consistent with hadrosaurids from the TMF. The data suggest size–frequency distributions of attritional samples underestimate age and overestimate growth rates, but when paired with osteohistology can provide unique life-history insights.

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