Seasonal Variation In Size Research Articles

Seasonal variation in size and composition of elk (Cervus canadensis) home range in central Appalachia

Home ranges are vitally important to an animal's behavior, survival, and reproduction. Variation in environmental conditions and landscape composition coupled with differences between sexes can influence home range structure, and understanding these differences is important for species management. Elk ( Cervus canadensisErxleben, 1777) are a widespread culturally important ungulate that has been well studied over portions of its range. Reintroduced populations in eastern North America, where conditions differ dramatically from those in the west, are comparatively understudied. Using Ornstein–Uhlenbeck movement models, we calculated season- and sex-specific home range and core areas for elk in Pennsylvania, USA. Results showed strong seasonal variation in sizes of core areas and home ranges, with summer ranges consistently smaller than other seasons. Home ranges were largely forested. However, forest cover of core areas was lower than home ranges. Proportion of open cover types was greater in core areas than home ranges. Use of timber harvests overall was low. However, among individuals with highly forested home ranges, timber harvests were strongly selected for in spring. This work highlights the regional specificity in the size, composition, and seasonality of elk home ranges, and stresses the need for additional context-specific research in understudied elk populations of forested eastern landscapes.

Body size variation in a guild of carrion beetles

Body size is a key biological trait, influencing the biomechanics, physiology, behaviour, and ecology of species. Describing variation in body size within and among co-occurring species within an ecological guild can provide important context for understanding the ecology of species and the structure of ecological communities. Here, we focus on a guild of carrion beetles (Coleoptera: Silphidae) co-occurring in southeastern Ontario, Canada. We examine how body size varies (i) among species, (ii) within species, including among sexes, and (iii) across the active season, contrasting estimates of size based on mass with those based on morphological structure (elytron length). We find that body size varies significantly both within and among species. Five focal species show evidence for sexual dimorphism in size. All focal species show significant seasonal variation in size, but these patterns differ across species, and depend on our estimates of size. Overall, the observed variation in body size is most consistent with widespread environmental constraints on size and (or) diverse selective pressures favouring different sizes within and among species. We discuss possible selective pressures acting on size within and among species; however, the causes and consequences of the variation in body size that we describe remain to be discovered.

Seasonal variations in size and intensity of the Indo-western Pacific warm pool in different sectors

The present study investigates the roles of solar radiation and monsoon wind in annual and semiannual variations of size and intensity of the Indo-western Pacific warm pool. The Indo-western Pacific warm pool is divided into four sectors with the equator and 100°E (north of the equator) and 135°E (south of the equator) longitude as the demarcations. These sectors display different seasonal variations in size and intensity and different roles of surface heat flux and oceanic processes. The size of the North Indian Ocean warm pool displays a semiannual variation with two peaks in May and October, while that in the other three sectors shows an annual variation. These features are attributable to a dominant role of solar radiation in the four sectors and an additional effect of the Asian monsoon in the North Indian Ocean sector. The intensity of the warm pool displays semianunal variations, with two peaks in May and August in the North Indian Ocean sector, April and November in the South Indian Ocean sector, May–June and September in the North Pacific Ocean sector and December and April in the South Pacific Ocean sector. The semiannual feature is associated with two effects of monsoon winds: wind-induced ocean advection and convection-related cloud-radiation changes. These two changes induce a decrease of sea surface temperature during the monsoon period, leading to the formation of semiannual variations in the size and intensity of the warm pool.

Morphometric relationships and seasonal variation in size, weight, and a condition index of post-settlement stages of the Caribbean spiny lobster.

Spiny lobsters have a protracted pelagic, oceanic larval phase. The final larval stage metamorphoses into a non-feeding postlarva (puerulus) that actively swims towards the coast to settle in shallow habitats and does not resume feeding until after the molt into the first-stage juvenile. Therefore, the body dimensions and nutritional condition of both settled pueruli and first juveniles are likely to vary over time, potentially playing a crucial role in the recruitment to the benthic population. We compared carapace length (CL), height (CH), and width (CW); total length (TL), and body weight (W) between pueruli and first juveniles of the Caribbean spiny lobster, Panulirus argus, as well as morphometric relationships between both developmental stages. Except for CL, all other dimensions were larger in first juveniles, but more markedly CH and W. The slopes of the CH vs CL, CW vs CL, and W vs CL regressions differed significantly between stages, and all log-transformed relationships showed isometry in both stages, except for the CH vs CL relationship, which showed positive allometry. These results reflect a morphological change from the flatter, more streamlined body of the puerulus, to the heavier, more cylindrical body of the juvenile. We also analyzed seasonal variations in CL, W, the W/CL index (a morphometric condition index), and a modified W/CL index (i.e. after controlling for a significant effect of CL) of both stages using individuals monthly collected over 12 consecutive seasons (Autumn 2010–Summer 2013). In both stages, all three variables exhibited significant seasonal variation. For pueruli, the modified W/CL index differed from average in only two seasons, winter 2011 (higher) and summer 2013 (lower), but showed great within-season variation (larger coefficients of variation, CV), potentially reflecting variability in nutritional condition of larvae prior to metamorphosis and in the distances swum by individual pueruli to the settlement habitats. For first juveniles, the modified W/CL index was higher than average in winter and spring 2011, and lower in autumn 2011 and winter 2012, but showed less within season variation (smaller CVs), suggesting a combination of carry-over effects of puerulus condition and effects of local conditions (e.g., food availability and predation risk). These findings warrant further investigation into factors potentially decoupling settlement from recruitment processes.

Cephalopod biodiversity in the vicinity of Bear Seamount, western North Atlantic based on exploratory trawling from 2000 to 2014

Bear Seamount (BSM) is the most inshore seamount in the New England Seamount chain. It is located within the U.S. Exclusive Economic Zone and is contained within the recently established Northeast Canyons and Seamounts Marine National Monument. In 2000, the National Oceanic and Atmospheric Administration’s (NOAA) National Systematics Laboratory began an exploratory trawling program to document nekton diversity at BSM and its vicinity. Here, we summarize eight exploratory sampling cruises conducted between 2000 and 2014, and describe the cephalopod biodiversity and assemblage structure around BSM. Over the course of 174 deep–midwater and 56 bottom tows, 5088 cephalopods were identified, measured, and documented. In total, 77 species were collected at BSM; 75 species were collected from midwater tows and 28 from benthic tows. Rarefaction curves did not reach an asymptote, suggesting that additional sampling will collect more species. Seventeen species accounted for 75% of the total midwater and bottom catch, including: Illex illecebrosus (n = 605), Magnoteuthis magna (n = 568), Abraliopsis morisii (n = 518), Abralia redfieldi (n = 358), Mastigoteuthis agassizii (n = 336), Histioteuthis reversa (n = 273), Taonius pavo (n = 239), Haliphron atlanticus (n = 195), Brachioteuthis beanii (n = 160), Ornithoteuthis antillarum (n = 153), Pterygioteuthis gemmata (n = 141), Pyroteuthis margaritifera (n = 120), Vampyroteuthis infernalis (n = 101), Chiroteuthis veranyi (n = 33), Bolitaena pygmaea (n = 30), Graneledone verrucosa (n = 11), and Stauroteuthis syrtensis (n = 29). Non-metric multidimensional scaling (NMDS) of significant analysis of similarity (ANOSIM) results showed that the 2000 cruise was different from other years, meteorological winter was different from other seasons, and that day and night shallow samples were different from each other and all other depths. Based on seasonal size variation in the most abundant taxa, we propose hypotheses of year-round, winter, and spring spawning for future critical assessment. This extensive description of the offshore cephalopod assemblage may be used to assess vulnerability to future environmental changes and human activities.

Seasonal variations in size, biomass, and elemental composition (CHN) of Halicarcinus planatus (Brachyura: Hymenosomatidae) larvae from the Beagle Channel, southern South America

The crab Halicarcinus planatus (Fabricius, 1775) is the only member of Hymenosomatidae that inhabits the southern tip of South America, and it is the only decapod species that reproduces twice a year in the Beagle Channel. In this study, we analysed seasonal variations in development duration, body size, biomass (dry weight), and elemental composition (CHN) of larvae from a population living at the southernmost limit of the species’ geographic range. Compared to offspring produced in December (early summer), larvae released in August (late winter) were on average larger and heavier, and they showed a higher carbon content (suggesting a larger lipid fraction). This pattern of intraspecific variation in larval size and biomass corresponds with minimum primary productivity in sub-Antarctic regions during winter, suggesting that large winter eggs may represent a reproductive adaptation to a regular pattern of variation in nutritional conditions, including food limitation in winter. As an additional or alternative explanation, also strong salinity fluctuations occurring in summer might reduce larval quality in the December cohort. In conclusion, seasonal variation in larval size and biomass may be related to variations in nutritional and/or physical factors.

Size variation and cell proliferation in chemosensory brain areas of a lizard (Podarcis hispanica): effects of sex and season

Many lizards rely on chemoreception for crucial aspects of their biology, including exploration, prey and predator detection, and intraspecific communication. Here we investigate sex and seasonal variation in size and proliferative activity in chemosensory areas of the lizard brain. We captured adult Iberian wall lizards (Podarcis hispanica) of either sex in the breeding (April) and non-breeding (November) season, injected them with 5-bromo-2'-deoxyuridine (BrdU) and killed them 3 weeks later. We removed the brains, measured the length of the olfactory bulbs, and counted BrdU-labelled cells in the main and accessory olfactory bulbs (MOB, AOB), lateral cortex (LC) and nucleus sphericus (NS). Our results show that, relative to body size, males have larger MOBs and AOBs than females; however, relative to brain size, males have larger AOBs, but not larger MOBs than females. Additionally, males produce more new cells than females in the olfactory bulbs, LC and NS. We failed to detect significant seasonal changes or sex x season interaction in size or proliferative activity in these areas. Sex differences in the addition of newly generated cells--mainly neurons--may be partly responsible for the size differences in chemosensory brain areas. The presence of sexual dimorphism in AOB is expected given the available behavioural evidence, which suggests that males of P. hispanica are more responsive than females to socially relevant chemical stimuli. This is the first demonstration of sexual dimorphism in size and proliferative activity in chemosensory areas of a non-mammalian species.

Seasonal variation on size and chemical constituents of Sargassum sinicola Setchell et Gardner from Bahía de La Paz, Baja California Sur, Mexico

SUMMARYInvestigation on seasonal variation in size and chemical constituents of Sargassum sinicola Setchell et Gardner from Bahía de La Paz, Baja California Sur, Mexico, was carried out from a control bed and compared with an experimental bed with artificial nutrients added. No significant differences were found between the control and experimental thalli for size or chemical composition, except for iodine and raw fiber. For control thalli the results were: size 7.5–56.0 cm, alginate yield 7.2–13.7%, viscosity 58.7–191.7 millipascal seconds (mPa s), mannitol 2.9–8.1%, raw fiber 5.5–7.5% and iodine 0.020–0.141%; while in the experimental thalli the size ranged from 7.5 to 80.3 cm and the alginate yield was 7.8–10.4%, viscosity 41.4–163.4 mPa s, mannitol 2.9–8.3%, raw fiber 5.9–10.7% and iodine 0.021–0.098%. These variations were related to its natural growth cycle, and showed reductions during the senescence period. Results suggest that S. sinicola is not affected by relatively low nutrient concentrations, and could be considered as raw material for alginate production.

VARIATION IN HOME RANGE OF THE SIDE-BLOTCHED LIZARD,UTA STEJNEGERI, IN COAHUILA, MEXICO

We studied seasonal variation in size and fidelity of home range in a population of eastern side-blotched lizards, Uta stejnegeri, in southern Coahuila, Mexico. Field work was carried out during the active seasons of 2002–2004. Home ranges during breeding and non-breeding seasons were larger for males than females and were reduced in both sexes during non-breeding months (autumn). There was greater intersexual overlap of home range during summer and less in autumn. Intrasexually, males had more overlap in home range than females (particularly during summer), which could be related to their large home ranges during that season. Fidelity to home range from one season to the next in a given year was similar in males and females. Although males had greater length and mass than females, neither measure correlated with size of home range. Density of adult lizards was negatively correlated with size of home range during the reproductive period. During non-reproductive months, density of all age classes combined was negatively correlated with size of home range. Our results indicate that home range sizes of U. stejnegeri vary considerably over the year and diverse factors are involved.

Seasonal variation in soil seed bank size and species composition of selected habitat types in Maputaland, South Africa

Seasonal variation in seed bank size and species composition of five selected habitat types within the Tembe Elephant Park. South Africa, was investigated. At three-month intervals, soil samples were randomly collected from five different habitat types: a, Licuati forest; b, Licuati thicket; c, a bare or sparsely vegetated zone surrounding the forest edge, referred to as the forest/grassland ecotone; d, grassland; and e, open woodland. Most species in the seed bank flora were either grasses, sedges, or forbs, with hardly any evidence of woody species. The Licuati forest and thicket soils produced the lowest seed densities in all seasons. Licuati forest and grassland seed banks showed a two-fold seasonal variation in size, those of the Licuati thicket and woodland a three-fold variation in size, whereas the forest/grassland ecotone maintained a relatively large seed bank all year round. The woodland seed bank had the highest species richness, whereas the Licuati forest and thicket soils were poor in species. Generally, it was found that the greatest correspondence in species composition was between the Licuati forest and thicket, as well as the forest/grassland ecotone and grassland seed bank floras.

Is there seasonal variation in size and mass of Red Admirals Vanessa atalanta on Capri, Italy?

I present data on seasonal variation in wing length and mass of Red Admirals Vanessa atalanta captured on Capri, Italy, during spring and autumn. The Red Admiral is a migratory butterfly that migrates north throughout Europe each year and then heads back south in the autumn. During the winter they are mostly found in the northern Mediterranean area where they previously were thought to hibernate, but recent data suggest that a new generation is produced before spring migration. The Red Admirals captured on Capri showed no difference in dry mass between the two seasons, when taking size in account, but had significantly longer wings in autumn. This suggests that a new generation is produced during winter.

Monitoring small fish populations in streams: A comparison of four passive methods

We analysed the relative efficiencies and size-selectivities of four different passive capture methods in a small coastal stream. We used plastic minnow traps (PM), metal minnow traps (MM) and two types of fyke nets differing in mesh size (F1, small meshed; F2, large meshed) to capture over 12,000 fish belonging to 11 species. Over 97% of captured fish were Andalusian toothcarp ( Aphanius baeticus), Iberian loach ( Cobitis paludica) and sand smelt ( Atherina boyeri). F1 was the most efficient trap type in capturing the three most abundant species. Catches by PM and F2 differed in taxonomic composition, the former being characterised by toothcarp and loach dominance and the latter by the catch of eel ( Anguilla anguilla) and grey mullets (Fam. Mugilidae). There were large differences in the size of fish captured in each trap type, with fish size following the pattern F2 > MM > F1 > PM. Small juveniles of the three dominant species were captured only in PM, thus enabling us to follow their seasonal size variation. However, PM traps were inefficient for sand smelt sampling and failed to catch large individuals of this species. This schooling and mainly pelagic species was more accurately monitored through the use of F1. Our results suggest that a combination of PM and F1 traps could improve the efficacy of small fish sampling in streams.

Geographic and Seasonal Variation in Size and Color of Adult Corn Leafhoppers (Hemiptera: Cicadellidae) from Mexico

We describe variation in wing length, head width, and color of the corn leafhopper, Dalbulus maidis (DeLong and Wolcott), in Mexico from 21 sites at nearctic and neotropical latitudes, from low ( 700 m) elevations, and wet season (June) and irrigated dry season (October) maize habitats. Female and male D. maidis were collected from 21 sites located from 15.72° N to 25.48° N latitude and 2–1,203 m elevation. Females and males from the northern nearctic latitudes were larger and darker than leafhoppers from the southern Neotropical latitudes. Elevation did not affect the size or color of female or male leafhoppers. At an irrigated site where maize is cultivated all year (Colima), females and males collected in October had longer wings than leafhoppers collected in June. At a nonirrigated site (Zapopan) where maize is cultivated only in the wet season, females collected in June had longer wings, wider heads, and were darker than females collected in October. Compared with leafhoppers living in irrigated maize habitats, D. maidis from maize cultivated only in the wet season have significant variations in body size and color, suggesting D. maidis adapts to survive seasonal harsh environments.

Spatial and seasonal variations in size, body volume and body proportion (prosome:urosome ratio) of the copepod Acartia tonsa in a semi-closed ecosystem (Berre lagoon, western Mediterranean)

Variations in size (prosome), body volume and proportion (prosome:urosome ratio) of female Acartia tonsa copepods were studied during three different seasons (June, October and November) in a network of 13 stations distributed throughout the Berre Lagoon, near Marseille. Strong morphological differences were found between the populations collected through the different seasonal surveys, but also between the different stations or groups of stations. They were related to the variations of environmental parameters (temperature, salinity, chlorophyll, particulate seston) according to the season and to the location of the stations (submitted to the marine influence in the south and to the intake of fresh water in the north of the lagoon). Considering all seasonal data, the size and body volume were inversely related to temperature. Body volume also showed a negative correlation with chlorophyll and carbon and a positive one with the C:N ratio of particles. The body proportion was positively correlated with temperature, chlorophyll and carbon. For each seasonal survey, the relationship between morphological features and environmental factors did not reach the significant level except in October when body proportion and volume were positively correlated to chlorophyll.Nevertheless, for each season, significant spatial changes in size or body proportion appeared in parts of the population of Acartia tonsa, in relation with local specific conditions of environmental factors, especially chlorophyll. These biometric differences suggest that individuals must develop in situ for at least the final period of larval growth, despite the dispersion effect caused by hydrodynamic movements. This stability in horizontal distribution may result from the diurnal vertical migrations of copepods between the surface and the bottom, two layers displaying currents of opposite directions. These results justify the use of somatic features (size and body proportion) to discriminate sets of individuals belonging to the same population. %

Functional response and potential predatory impact of Tortanus dextrilobatus, a carnivorous copepod recently introduced to the San Francisco Estuary

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 277:167-179 (2004) - doi:10.3354/meps277167 Functional response and potential predatory impact of Tortanus dextrilobatus, a carnivorous copepod recently introduced to the San Francisco Estuary Rian C. Hooff1,2,*, Stephen M. Bollens1,3 1Romberg Tiburon Center for Environmental Studies and Department of Biology, San Francisco State University, 3150 Paradise Drive, Tiburon, California 94920, USA 2Present address: Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, Oregon 97365, USA 3Present address: School of Biological Sciences, Washington State University Vancouver, 14204 NE Salmon Creek Avenue, Vancouver, Washington 98686, USA *Email: rian.hooff@oregonstate.edu ABSTRACT: Despite a dramatic increase in the introduction of non-indigenous estuarine zooplankton in recent decades, the trophic implications of such introductions have rarely been quantified. Here we investigate predation rates of Tortanus dextrilobatus, a carnivorous copepod recently introduced to the San Francisco Estuary that achieves peak abundances in excess of 1000 ind. m-3. The functional response of T. dextrilobatus feeding upon 2 copepod prey types‹the non-indigenous cyclopoid Oithona davisae, and the Œnative¹ calanoid Acartia (Acartiura) sp.‹was described by a type II functional response (Ivlev function) at 2 experimental temperatures. In 3 of these 4 treatments, 90% Imax was achieved within a naturally occurring range of prey densities. Taxon-specific seasonal size variation was identified, and carbon-based consumption values were used to determine temperature-dependent rates of predation on both prey types. These empirically derived consumption rates and temperature dependence values were then applied to broadscale surveys (1997 to 1999) of zooplankton community composition in order to estimate the predatory impact of T. dextrilobatus upon prey populations in the San Francisco Estuary. Predatory impact estimates (% population consumed d-1) greater than 1% occurred on a regular basis when T. dextrilobatus was abundant, with maxima exceeding 20, 65, and 25% for O. davisae, Acartia (Acartiura) sp. and all Copepoda, respectively. These observations support the hypothesis that non-indigenous invertebrate zooplanktivores can play a significant role, at least seasonally or episodically, in the secondary production dynamics of aquatic ecosystems. KEY WORDS: Zooplankton ecology · Feeding · Predation · Copepods · Tortanus dextrilobatus · Non-indigenous · Invasion · San Francisco Estuary Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 277. Online publication date: August 16, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Variation of oceanographic processes affecting the size of pink shrimp ( Farfantepenaeus duorarum) postlarvae and their supply to Florida Bay

Pink shrimp ( Farfantepenaeus duorarum) postlarvae were collected monthly with moored channel nets from October 1997 to June 1999 at Whale Harbor (WH) and Long Key (LK) Channels, two channels at the east and west ends of the Middle Florida Keys that connect the Atlantic Ocean with Florida Bay, the main nursery ground of this species in south Florida. The density influx of pink shrimp postlarvae through these two channels differed in magnitude and seasonal patterns. The monthly influx of postlarvae at LK was lower in magnitude but steadier than at WH. LK showed the highest postlarval influx in late spring–summer. Postlarval influx through WH further downstream showed both spring–summer and winter peaks. The spring–summer peaks correspond with favorable wind and current conditions. In contrast, the winter peaks occurred when cyclonic eddies were detected passing through the Middle Florida Keys. These cyclonic eddies induced coastal countercurrent flow that favors onshore larval transport. The position of the leading edge of the eddy relative to the channels may cause the temporal variability observed in the temporal postlarval influx patterns between channels. A seasonal size variation in postlarvae was also observed at both sampling sites. Postlarvae captured during the winter months were significantly larger than those captured during the summer months. The number of rostral spines, a morphological feature generally correlating with the number of moults and age, also varied seasonally but with a trend opposite to that of the body size, which may indicate a lengthening of the intermoult period during wintertime. The reasons for the seasonal differences in growth rates and, possibly, different lengths of time in the currents, are yet to be resolved.

Effects of trap retention on body composition of live meadow voles.

In many studies of small mammals, body mass has been used as an estimate of body size (Iskjaer et al. 1989), seasonal variation in size (Barbehenn 1955; Iverson and Turner 1974), nutritional status (Batzli and Esseks 1992), or growth (Chitty 1952; Barbehenn 1955; Brown 1973; Iverson and Turner 1974). However, body mass has been shown to be variable, especially when animals are retained in live traps. A single live trap capture can decrease total body mass up to 10%, as shown in meadow voles, Microtus pennsylvanicus, and in deer mice, Peromyscus maniculatus (Kaufman and Kaufman 1989, 1994). In addition, individuals will continue to lose mass with repeated live trap captures over short time periods (Brown 1973; Iverson and Turner 1974; Korn 1987), with body mass losses from 4% to 9% in prairie voles, Microtus ochrogaster, captured repeatedly over a 3-d period (Slade and Iskjaer 1990; Slade 1991). These results indicate that, when using body mass measured from animals captured in live traps, the mass fluctuations create additional uncertainty and inflate the variation in one’s data. The loss of body mass could be caused by capture stress and handling, food deprivation and/or dehydration because of trap confinement, lipid or fat-free tissue catabolism, or any combination thereof. To date, no one has reported the effects of live trap retention on the body composition of a captured animal. Historically, body composition studies involving small mammals employ snap traps followed by chemical extraction of lipids. In this study, we used a repeatable, noninvasive technique (EM-SCAN)

Strong influences of larval diet history on subsequent post-settlement growth in the freshwater mollusc Dreissena polymorpha.

A significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing the life history and development of freshwater invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the proposal that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells, which are deficient in polyunsaturated fatty acids (PUFAs) and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the post-metamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet. Hence, low food quantity or low food quality during the larval stage of D. polymorpha, lead to irreversible effects for post-metamorphic animals and are related to inferior competitive abilities.

A new genus of viviparous gyrodactylid (Monogenea) from the Great Barrier Reef, Australia with descriptions of seven new species

Acanthoplacatus gen. nov., a new genus of viviparous gyrodactylid, is described from the fins and skin of siganid fishes from the Great Barrier Reef, Australia. The genus is characterized by a muscular, tube-like haptor with 16 marginal hooks on the posterior margin. The ventral lobe of the haptor is located anteriorly relative to the dorsal lobe and contains a pair of hamuli and a ventral bar with posteriorly-projecting ventral bar membrane. A dorsal bar is absent. Five pairs of posterior gland cells surround the posterior terminations of the gut. The male copulatory organ is a muscular, non-eversible bulb with several spines around the distal opening. Species of Acanthoplacatus have a bilateral excretory system consisting of six pairs of flame cells and a pair of excretory bladders. Seven new species are described: Acanthoplacatus adlardi sp. nov. and A. amplihamus sp. nov. from Siganus punctatus (Forster, 1801), A. brauni sp. nov. from S. corallinus (Valenciennes, 1835), A. parvihamus sp. nov. from S. vulpinus (Schlegel and Mueller, 1845), A. puelli sp. nov. from S. puellus Schlegel, 1852, A. shieldsi sp. nov. from S. lineatus (Valenciennes, 1835) and A. sigani sp. nov. from S. fuscescens (Houttuyn, 1782). Species can be discriminated by shape and size of the hamuli, marginal hooks and ventral bar and by male copulatory organ sclerite morphology. Three species (A. brauni sp. nov., A. shieldsi sp. nov. and A. sigani sp. nov.) were assessed for seasonal variation of sclerite size. Ten of thirteen morphological characters showed seasonal variation in size for at least one of the species. The characters were longer in winter except dorsal root tissue cap width. Only one character, marginal hook length, showed significant seasonal variation for all three species. Species of Acanthoplacatus were observed to attach using only the marginal hooks and the role of hamuli in attachment is unclear. The dorsal fin of the host is the preferred site for most species but the anal fin, caudal fin and body surfaces are preferred by some species. Prevalences for species range from 57 to 100%.

Biological observations on Tupiperla (Plecoptera: Gripopterygidae).

Tupiperla illiesi fly along the year in the coastal mountains of southeastern Brazil, with larger numbers during the warmer rainy season. In the seasonal tropical climate of Central Brazil and Serra do Cipó, MG, T oliveirai and T. gracilis, respectively, fly along the year but the pattern is still not known. In the higher elevation (ca. 1600 m a.s.l.) of Campos do Jordao, SP, species of Tupiperla may not fly during the colder months. Seasonal size variation, a phenomenon still little understood, occurred both in tropical and subtropical climates of the states of Goiás and São Paulo.