Distribution, Growth, and Seasonal Abundance of Hyalella azteca (Amphipoda) in Relation to Sediment Microflora

1970 ◽  
Vol 27 (4) ◽  
pp. 685-699 ◽  
Author(s):  
Barry T. Hargrave
Keyword(s):  
Body Size ◽  
Egg Production ◽  
Sediment Cores ◽  
Hyalella Azteca ◽  
Maximum Density ◽  
Seasonal Abundance ◽  
Juvenile Survival ◽  
Substrate Choice ◽  
Deposit Feeding ◽  
The Vertical Distribution

Growth, density, and body size of the deposit-feeding amphipod Hyalella azteca, and its food, epibenthic algae, and sediment microflora, were greatest in shallow-water areas of Marion Lake. The vertical distribution of Hyalella was limited to the upper 2 cm of sediment cores. Highest concentrations of sedimentary chlorophyll and lowest concentrations of nondigestible ligninlike material also occurred at the sediment surface.In laboratory substrate-choice experiments, Hyalella differentiated between sediments with different concentrations of microorganisms, and growth depended upon the quantity of microflora in the diet. In Marion Lake, increased growth of Hyalella during June was independent of temperature and closely correlated with increased rates of epibenthic primary production.Egg production, related to body size in a nonlinear manner, began during May as growth rates increased. As a combined result of egg production and juvenile survival, the maximum density of Hyalella in Marion Lake was reached in August.

scholarly journals Emergence ecology of the critically endangered Urothemis edwardsii in a new colonized site in El Kala National Park (Algeria): conservation implications

2019 ◽  
pp. 137-142
Author(s):  
Baaloudj Affef
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Microhabitat Selection ◽  
Conservation Implications ◽  
And Behavior ◽  
The Relationship ◽  
The Vertical Distribution ◽  
Dragonfly Species

Urothemis edwardsii is one of the most threatened dragonfly species in the Mediterranean. Recent investigations and conservation efforts have increased the local geographic distribution of the species in Northeast Algeria, where a new population (named El Graeate) has been discovered. In the absence of information about the biology and behavior of U. edwardsii in this new site, a study was conducted on the emergence ecology of the species taking into account the temporal pattern of emergence, sex ratio, body size and microhabitat selection. Emergence, which was quite asynchronous, lasted for 50 days, with 50% of the population emerging within the first half of the period. Sex ratio at emergence was slightly female biased despite the absence of sexual size dimorphism, suggesting that size is not the only driving force behind mortality bias during the larval stage. There was a slight seasonal increase in the body size of exuviae (exoskeletons) in both sexes. Microhabitat selection, assessed as the vertical stratification of exuviae at ecdysis, was positively correlated with the height of supporting plants, but the relationship reached a plateau suggesting that there are predetermined limits to the vertical distribution of exuviae. These data will be essential for the future species protection, restoration and management attempts in the region.

scholarly journals Body size and the timing of egg production in parasitoid wasps: a comparative analysis

2003 ◽  
Vol 17 (3) ◽  
pp. 375-383 ◽  
Author(s):  
M. A. Jervis ◽  
P. N. Ferns ◽  
G. E. Heimpel
Keyword(s):  
Body Size ◽  
Comparative Analysis ◽  
Egg Production ◽  
Parasitoid Wasps

Reproductive performance in a phyletic dwarf, the spider crab Petramithrax pygmaeus (Bell, 1836) (Decapoda: Brachyura: Mithracidae)

2020 ◽  
Vol 40 (3) ◽  
pp. 325-329
Author(s):  
Joshua T Fields ◽  
Hayden K Mullen ◽  
Clayr M Kroenke ◽  
Kyla A Salomon ◽  
Abby J Craft ◽  
...  
Keyword(s):  
Body Size ◽  
Reproductive Performance ◽  
Related Species ◽  
Egg Production ◽  
Marine Invertebrates ◽  
Small Body ◽  
Reproductive Investment ◽  
Spider Crab ◽  
Closely Related Species ◽  
Body Sizes

Abstract The spider crab Petramithrax pygmaeus (Bell, 1836), a phyletic dwarf, was used to test predictions regarding reproductive performance in small marine invertebrates. Considering the disproportional increase in brooding costs and the allometry of egg production with increasing body size, it was expected that this minute-size species would produce large broods compared to closely related species that attain much larger body sizes. Fecundity in P. pygmaeus females carrying early and late eggs varied, respectively, between 17 and 172 eggs crab–1 (mean ± SD = 87.97 ± 48.39) and between 13 and 159 eggs crab–1 (55.04 ± 40.29). Females did not experience brood loss during egg development. Egg volume in females carrying early and late eggs varied, respectively, between 0.13 and 0.40 mm3 (0.22 ± 0.07) and between 0.15 and 0.42 mm3 (0.26 ± 0.06 mm3). Reproductive output (RO) varied between 0.91 and 8.73% (3.81 ± 2.17%) of female dry body weight. The RO of P. pygmaeus was lower than that reported for closely related species with larger body sizes. The slope (b = 0.95 ± 0.15) of the line describing the relationship between brood and parental female dry weight was not statistically significant from unity. Overall, our results disagree with the notion that the allometry of gamete production and increased physiological costs with increased brood size explain the association between brooding and small body size in marine invertebrates. Comparative studies on the reproductive investment of brooding species belonging to monophyletic clades with extensive differences in body size are warranted to further our understanding about disparity in egg production in brooding marine invertebrates.

Bionomics of the Crapemyrtle Aphid (Homoptera: Aphididae)2

1992 ◽  
Vol 27 (4) ◽  
pp. 445-457 ◽  
Author(s):  
David R. Alverson ◽  
R. Ken Allen
Keyword(s):  
South Carolina ◽  
Maximum Density ◽  
Reproductive Age ◽  
Seasonal Abundance ◽  
Sharp Decline ◽  
Temperature Dependent ◽  
Early Fall ◽  
Predator Complex ◽  
Laboratory Time ◽  
Aphid Populations

Populations of the crapemyrtle aphid, Tinocallis kahawaluokalani (Kirkaldy), in South Carolina develop from overwintering eggs which are distributed near new emerging leaves. Seasonal abundance is typically bimodal and locally concurrent within a season, but without consistency in timing or intensity of occurrence between seasons or host plant cultivars. On leaves of Lagerstoemia indica L. (‘Carolina Beauty’ [CB]) in the laboratory, time of development was temperature-dependent, requiring 14 d for development through four instars to the adult at 18° C, 6 d at 26° C, and 5 d at 32° C. Longevity of adult virginoparae was ca. 17 d, 13 d, and 8 d, at these temperatures, respectively, and was at least as long on leaves of the apparently less susceptible ‘Natchez’ (N) cultivar. Fecundity was greatest at 18° and 26° C, averaging 56 and 61 offspring/female, respectively, on CB leaves and 54 and 71 offspring/female on N leaves. Fecundity declined sharply to 27 and 18 offspring/female on CB and N, respectively, at 32° C. Maximum daily fecundity rates were attained within 5 d of adult reproductive age on both host cultivars, then declined at temperature-dependent rates. Male and female sexuales were produced in early fall as mixed progeny with sexuparae at a ratio of 12.2: 9.7: 3.5 sexuparae: oviparae: males. Longevity of males was 7 d; oviparae lived 8 d and produced 1 to 6 eggs each. Syrphids and coccinellids were principle components of the predator complex associated with dynamics in the crapemyrtle aphid populations. Population dynamics in the absence of predators was characterized by a maximum density of ca. 200 aphids/leaf on CB attainable within 5 wk of inoculation with a single aphid followed by a sharp decline. Population development potential decreased as the season progressed. A braconid, Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae), reared from mummies of the crapemyrtle aphid in a greenhouse, constitutes the first reported parasitoid.

Intraspecific variation in reproductive effort by female Parapediasia teterrella (Lepidoptera: Pyralidae) and its relation to body size

1990 ◽  
Vol 68 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Larry D. Marshall
Keyword(s):  
Life History ◽  
Body Size ◽  
Egg Production ◽  
Egg Size ◽  
Reproductive Effort ◽  
Life History Evolution ◽  
Reproductive Parameters ◽  
Trade Offs ◽  
Egg Number ◽  
Lepidoptera Pyralidae

Daily egg production of the moth Parapediasia teterrella declined over the life-span of the female but egg size remained constant. The absence of water resulted in lower fecundity and early mortality. Egg size and lifetime fecundity showed considerable inter-individual variation and large females produced more and larger eggs than their smaller counterparts. Large females expended greater reproductive effort than small females. Hatching success was negatively related to egg size. In spite of this, large females laying large eggs had higher fitness than small females. I postulate that multiple reproductive strategies within a species, resulting from differences in reproductive effort expended, may explain why expected trade-offs in reproductive parameters (e.g., egg size versus egg number) were not found in this species. Furthermore, I argue that the prevalent interpretation of life-history evolution (that body size is the important determining parameter of life-history parameters) may reflect correlation of body size with reproductive effort, and reproductive effort may be more important in determining the nature of trade-offs between reproductive parameters.

Reproductive patterns of European pond turtles differ between sites: a small scale scenario

2015 ◽  
Vol 36 (4) ◽  
pp. 339-349
Author(s):  
Marco A.L. Zuffi ◽  
Elena Foschi
Keyword(s):  
Body Size ◽  
Egg Production ◽  
Shell Height ◽  
The Body ◽  
Small Scale ◽  
Central Mediterranean ◽  
Population Structures ◽  
Body Sizes ◽  
Reproductive Females ◽  
Similar Body

From 1996 to 2002, we studied the body size, measures of reproductive strategy (relative clutch mass and delayed reproduction at sexual maturity), and reproductive output (clutch frequency and annual egg production) of female European Pond turtles,Emys orbicularis, at two sites separated by 12 km in central Mediterranean Tuscany (San Rossore and Camp Darby, central northern Italy). Females did not reproduce at the first appearance of external sexual characters, but reproduced at larger sizes, probably as older turtles. Among years, reproductive females were more common than were non-reproductive females, yet both groups had similar body sizes. Body size (carapace length and width, plastron length and width, shell height and body mass) varied between localities and among years. Body size differed between reproductive and non reproductive females in Camp Darby, but not in San Rossore females. Shell volume did not vary among years, nor between localities, nor between reproductive status. Reproductive females had higher body condition indices (BCI) than did non-reproductive females, while BCI did not differ between females laying one clutch and females laying multiple clutches. Clutch size did not vary among years. One clutch per year was much more frequent than multiple clutches, and multiple clutches were more frequent in Camp Darby than in San Rossore females, likely due to differences in population structures between sites.

Studies on Ergasilus labracis Krøyer (Cyclopidea: Ergasilidae) parasitic on striped bass, Morone saxatilis, from the lower Chesapeake Bay. I. Distribution, life cycle, and seasonal abundance

1976 ◽  
Vol 54 (4) ◽  
pp. 449-462 ◽  
Author(s):  
I. Paperna ◽  
D. E. Zwerner
Keyword(s):  
Life Cycle ◽  
Chesapeake Bay ◽  
Striped Bass ◽  
Egg Production ◽  
Developmental Stages ◽  
Morone Saxatilis ◽  
Early Spring ◽  
Seasonal Abundance ◽  
Free Living ◽  
Winter Peak

Information on the distribution, life cycle, and seasonal abundance of the copepod Ergasilus labracis Krøyer, parasitic on the gills of lower Chesapeake Bay striped bass, Morone saxatilis (Walbaum), is presented after a 12-month survey. The overall prevalence of E. labracis was 90% in all localities sampled and it was found to be as euryhaline as its host; it has been found in salinities from 0.l‰ to 32.0‰. E. labracis was present and reproductively active throughout the year, suffering only a temporary slowdown in egg production at the beginning of the winter. Peak invasion of striped bass gills by infective larvae occurred during April and May; minor peaks were also recorded during July and October. The free-living stage was estimated to last as long as 6 weeks during early spring. Duration of other developmental stages was also extrapolated. Attempts to rear larvae in the laboratory past the metanauplius stage failed. Larvae could be kept for a maximum of 23 days after hatching if fed nannoplankton and kept at 20 °C in river water of 16–18‰.

Schadstoff-Untersuchungen an datierten Sedimentkernen aus dem Bodensee / Pollution Research on Dated Sediment Cores from Lake Constance

1977 ◽  
Vol 32 (11-12) ◽  
pp. 913-919 ◽  
Author(s):  
German Müller
Keyword(s):  
Heavy Metals ◽  
Sediment Cores ◽  
Enrichment Factors ◽  
Lake Constance ◽  
General Distribution ◽  
Common Source ◽  
Pollution Research ◽  
Polycyclic Aromatic ◽  
Anthropogenic Processes ◽  
The Vertical Distribution

Abstract The vertical distribution of eight heavy metals (Hg, Cu, Zn, Cr, Co, Ni, Pb, Cd) in dated sediments of four sedimentary profiles from the central part of Lake Constance was examined. From 1900 to about 1960 - 1970, a general increase of all heavy metals was observed. After this time, the concentrations of most of the metals decreased. As compared with pre-1900 “natural” metal concentrations, Cd and Pb have been enriched the strongest (enrichment factors 4.0 and 3.8 resp.), whereas Ni and Co exhibit least civilizational influences (enrichment factors 1.5 and 1.9 resp.). Cu, Cr, Zn and Hg were enriched by a factor between 2 - 3. Elements which were not influenced by anthropogenic processes - such as K and Li - remained unaffected over the whole vertical sequence. Polycyclic aromatic hydrocarbons (PAH) which were also studied in the same sediment material by Grimmer and Böhnke show a similar pattern. Within a sedimentary profile the concentration ratio benzo (a) pyrene: cadmium remained about constant. Combustion of coal is believed to be the common source of both heavy metals and PAH and seems to be responsible for the general distribution pattern of both groups of pollutants. In addition, local sources - both domestic and industrial - are assumed to have delivered additional heavy metal pollution.

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