scholarly journals Reproductive activities of two zooplanktivorous clupeid fish in relation to the seasonal abundance of copepod prey in the northern end of Lake Tanganyika

2020 ◽  
Vol 144 (2) ◽  
Author(s):  
N'sibula Mulimbwa ◽  
Jouko Sarvala ◽  
Joost A.M. Raeymaekers
Keyword(s):  
Rainy Season ◽  
Lake Tanganyika ◽  
Gonadosomatic Index ◽  
Reproductive Investment ◽  
Seasonal Abundance ◽  
Pelagic Species ◽  
Investment In Reproduction ◽  
Species Specific ◽  
Reproductive Activities ◽  
Limnothrissa Miodon

Reproductive activities of two commercially exploited clupeid fishes (Stolothrissa tanganicae and Limnothrissa miodon) in the northern end of Lake Tanganyika (Bujumbura sub-basin) were investigated during two different years (2004-2005 and 2007-2008). We hypothesized that the timing of largest reproductive investment in these pelagic species coincides with the onset of the rainy season and the highest abundance of copepod prey. For S. tanganicae, the gonadosomatic index (GSI) was significantly higher prior to the onset of the rainy season, and this was observed in both years. For L. miodon, however, this pattern was overall weaker and only statistically significant in 2004-2005. In both species, spawning activities did not seem to be adjusted to provide optimal feeding conditions for the larvae. Instead, investment in reproduction seemed to be related to the availability of copepods in the preceding months. We conclude that the timing of reproductive activities in these clupeids is species-specific, and might be subject to strong year-to-year variation.

STUDY ON DIVERSITY AND DISTRIBUTION OF ANTS (HYMENOPTERA: FORMICIDAE) IN URBAN AND PERIURBAN AREAS OF AURANGABAD CITY, MAHARASHTRA, INDIA

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
S. D. CHATE ◽  
R. J. CHAVAN
Keyword(s):  
Rainy Season ◽  
Winter Season ◽  
Seasonal Abundance ◽  
Urban Region ◽  
Ant Community ◽  
Community Variation

The present study deals with the ant community variation in and around Aurangabad city. During the study total 16 species of ants belonging to twelve genera and four subfamilies were reported in eight habitat from urban and periurban regions. Abundance of ants was more in peri-urban region as compared to urban region. Subfamily myrmicinae was more dominant as compared to other subfamilies. Seasonal abundance of ants was seen to be more in winter season and less in rainy season.

scholarly journals Adult body growth and reproductive investment vary markedly within and across Atlantic and Pacific herring: a meta-analysis and review of 26 stocks

2021 ◽  
Author(s):  
Thassya C. dos Santos Schmidt ◽  
Doug E. Hay ◽  
Svein Sundby ◽  
Jennifer A. Devine ◽  
Guðmundur J. Óskarsson ◽  
...  
Keyword(s):  
Egg Size ◽  
Meta Analysis ◽  
Reproductive Investment ◽  
Body Growth ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Atlantic Herring ◽  
Additional Information ◽  
Trade Offs ◽  
Investment In Reproduction

AbstractLife-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.

The effects of capital on an income breeder: evidence from female Columbian ground squirrels

2005 ◽  
Vol 83 (4) ◽  
pp. 546-552 ◽  
Author(s):  
David R Broussard ◽  
F Stephen Dobson ◽  
J O Murie
Keyword(s):  
Path Analysis ◽  
Observational Data ◽  
Life Histories ◽  
Reproductive Investment ◽  
Ground Squirrels ◽  
Initial Capital ◽  
Spermophilus Columbianus ◽  
Live Trapping ◽  
Investment In Reproduction ◽  
Columbian Ground Squirrels

To maximize fitness, organisms must optimally allocate resources to reproduction, daily metabolic maintenance, and survival. We examined multiple years of live-trapping and observational data from a known-aged population of female Columbian ground squirrels, Spermophilus columbianus (Ord, 1815), to determine the influences of stored resources and daily resource income on the reproductive investments of females. We predicted that because yearling females were not fully grown structurally while producing their first litter, they would rely exclusively on income for reproduction, while reproductive investment in older females (≥2 years of age) would be influenced by both stored resources (capital) and daily income. Results from path analysis indicated that both yearlings and older females were income breeders. However, initial capital indirectly influenced investment in reproduction of yearling and older females. Females with the greatest initial capital maintained high body masses while investing relatively more income in reproduction. By considering influences of both capital and income, important relationships can be revealed between these resources and their influence on life histories.

Conserved growth rate and age structure of Xenopus laevis in the edge and core of an expanding population

2019 ◽  
Vol 128 (1) ◽  
pp. 122-129 ◽  
Author(s):  
Julien Courant ◽  
Layla Adil ◽  
Barbara De Kegel ◽  
Dominique Adriaens ◽  
Anthony Herrel
Keyword(s):  
Growth Rate ◽  
Xenopus Laevis ◽  
Age Structure ◽  
Reproductive Investment ◽  
Individual Growth ◽  
Evolutionary Mechanisms ◽  
Range Edge ◽  
Investment In Reproduction ◽  
Range Core ◽  
Expanding Population

Abstract Invasive species represent a unique opportunity to study the evolutionary mechanisms driving range expansions. Although range expansion is expected to be associated with increased reproduction and dispersal at the range edge, Xenopus laevis seems to decrease its reproductive investment and to enhance dispersal at the range edge. Evidence of increased dispersal at the edge of expanding populations occurring simultaneously with a faster growth rate has been reported for other organisms. Here, we focused on the growth rate and age structure at the range edge vs. the range core in an expanding population of X. laevis. We used skeletochronology to characterize the age of 250 individuals captured at the range core and edge of this expanding population. Using the Von Bertalanffy equation, we then compared individual growth rates between locations. We found no significant changes in growth rate or age structure between edge and core samples. This result suggests that the reduced investment in reproduction recorded in another study at the range edge might compensate for the increased dispersal without impacting growth in this population. This implies that the resource allocation in an expanding population might thus be more diverse than commonly assumed.

scholarly journals Length-weight relation, condition factor and gonadosomatic index of the whitemouth croaker, Micropogonias furnieri (Desmarest, 1823) (Actinopterygii: Sciaenidae), caught in Lençóis Bay, state of Maranhão, eastern Amazon, Brazil

2017 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
James Werllen de Jesus Azevedo ◽  
Antonio Carlos Leal de Castro ◽  
Marcelo Henrique Lopes Silva
Keyword(s):  
Sex Ratio ◽  
Rainy Season ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Length Distribution ◽  
The State ◽  
Allometric Growth ◽  
First Semester ◽  
Length Relationship ◽  
Micropogonias Furnieri

Abstract The whitemouth croaker, Micropogonias furnieri, which is exploited off the state of Maranhão, Brazil, reinforces the need for maintenance programs of natural stocks of this species to assist in the management of this exploited resource. The aim of the present study was to describe aspects regarding its reproductive characteristics (gonadosomatic index and condition factor) and also the length distribution and weight-length relationships. The fish were caught in Lençóis Bay in the state of Maranhão (eastern Amazon) between June 2010 and July 2011. A total of 570 individuals were caught (318 males and 252 females). Differences in length were found between the sexes, with females larger than males. The sex ratio indicated a tendency for females to be more abundant in the rainy season (first semester), whereas males predominated in the dry season (second semester). The weight-length relationship indicated negative allometric growth for both sexes. The analysis of the variation in the condition factor suggests that lower values coincided with higher gonadosomatic index values and that this factor is a good reproductive indicator for M. furnieri in the region.

Dispersal and survival of Anopheles funestus and A. gambiae s.l. (Diptera: Culicidae) during the rainy season in southeast Tanzania

1998 ◽  
Vol 88 (5) ◽  
pp. 561-566 ◽  
Author(s):  
W. Takken ◽  
J.D. Charlwood ◽  
P.F. Billingsley ◽  
G. Gort
Keyword(s):  
Rainy Season ◽  
Light Trap ◽  
Survival Rates ◽  
Anopheles Funestus ◽  
The Other ◽  
Movement Rates ◽  
Fluorescent Powder ◽  
Local Topography ◽  
Release Area ◽  
Species Specific

AbstractIn a rural area of southeastern Tanzania, studies were undertaken on the dispersal and survival of Anopheles funestus Giles and A. gambiae Giles s.l. during the rainy season. Blood fed, resting mosquitoes were collected indoors, marked with fluorescent powder and released on the same day from two different sites in the study area. For two weeks indoor resting mosquitoes were collected from 11 houses in the release area. Additional collections were made with a light trap from a sentinel house in the centre of the study area. Anopheles funestus was more abundant than A. gambiae s.l. Of 4262 A. funestus and 645 A. gambiae s.l. released, 4.3% and 7.4%, respectively, were recaptured. Dispersal of mosquitoes was not random: one of three areas was favoured significantly more than the other areas, as shown by the recapture and movement rates of marked mosquitoes. Based on the regression of the recapture rate, estimated daily survival rates of A. funestus and A. gambiae s.l. were 0.63 and 0.78, respectively. These were significantly different. The differences in dispersal and survival rates between the two species are discussed in view of local topography and species-specific characteristics.

scholarly journals Gametogenesis in Pubescent Heterobranchus longifilis (Teleostei: Clariidae) (Val. 1840) Attaining Puberty Under Artificial Conditions; and Under Rainy and Dry Season Conditions, in Tropical Earthen Ponds

2005 ◽  
Vol 18 (2) ◽  
Author(s):  
C.O. OFOR
Keyword(s):  
Rainy Season ◽  
Sexual Maturity ◽  
Gonadosomatic Index ◽  
Dry Season ◽  
Ovarian Maturation ◽  
Earthen Ponds ◽  
Group 3 ◽  
Group 2 ◽  
Heterobranchus Longifilis ◽  
Group 1

Three groups of Heterobranchus longifilis attained puberty under three environmental conditions. In experiment 1, 23 fish (10 males, 13 females) were raised in the rainy season, (group 1). In experiment 2, 90 fish (39 males, 51 females) were raised in a recirculation system (group 2). In experiment 3, 160 fish (73 males, 87 females) were raised in the dry season (group 3 ). Groups 1 and 3 were raised in outdoor earthen ponds. Gametogenesis in the groups was studied using histology and gonadosomatic index. Oocytes maturation commenced at 9½ months in all groups and lasted 67 days in group 1, and about 130 days in groups 2 and 3. Sexual maturity occurred at 352, 427, and 425 days respectively in groups 1, 2 and 3. It seems that the key point in ovarian maturation in pubescent Heterobranchus longifilis is 9½ months, with further oogenesis being influenced by rainfall. The time spent from here to sexual maturity onset may be shortened if it falls within the rainy season. The period may run its full course if it falls within the dry season, or the rearing environment is indoor. The application of these observations in the aquaculture of the species is discussed.

scholarly journals Sandflies (Diptera: Psychodidae) of the Amazônia of Maranhão. V. Seasonal occurrence in ancient colonization area and endemic for cutaneous leishmaniasis

2001 ◽  
Vol 61 (1) ◽  
pp. 107-115 ◽  
Author(s):  
J. M. M. REBÊLO ◽  
S. T. de OLIVEIRA ◽  
F. S. SILVA ◽  
V. L. L. BARROS ◽  
J. M. L. COSTA
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Rainy Season ◽  
Seasonal Abundance ◽  
Seasonal Occurrence ◽  
Annual Species ◽  
Light Traps ◽  
Dry Period ◽  
Municipal District ◽  
Set Up ◽  
Eleven Species

In this paper, the seasonal abundance of 25 sandfly species (1 of the Brumptomyia genus and 24 of the Lutzomyia genus) found at P1V5, municipal district of Buriticupu, Maranhão State, is discussed. The capture was carried out from 18:00 P.M. to 6:00 A.M., once a month, from January to December 1996. CDC light traps were set up in the forest, in the peri and intradomicile environments. Five species were only found in the rainy season (January to June), being represented by one or two individuals; eight species occurred only in the dry season (July to December) and eleven species appeared in both seasons. The most frequent species in the dry period were: L. whitmani (26.3%), L. serrana (23%), L. choti (22.8%), L. evandroi (7.5%), L. longipalpis (5.8%), L. termitophila (3.3%), L. shannoni (3%) and L. migonei (2.5%). In the rainy season, L. whitmani was the prevailing species (74%), followed by L. termitophila (4%), L. umbratilis (3.4%), L. serrana (2.8%), L. evandroi (2,8%) and L. claustrei (2.4%). L. whitmani was thought to be an annual species, occurring in the entire year of study. The others species, with exception to L. serrana and L. evandroi, showed a seasonal, punctual or peripheric pattern.

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