HEMATOLOGIC METRICS FROM OLROG'S GULL (LARUS ATLANTICUS) DURING THE NONBREEDING SEASON IN ARGENTINA

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Germán O. García ◽  
Melina V. Castano ◽  
Jesica A. Paz ◽  
Carla A. Paterlini ◽  
Francisco Zumpano ◽  
...  
Keyword(s):  
Nonbreeding Season ◽  
Olrog’S Gull

Effect of Melatonin on Telocytes in the Seminal Vesicle of the Soay Ram: An Immunohistochemical, Ultrastructural and Morphometrical Study

2016 ◽  
Vol 203 (1) ◽  
pp. 29-54 ◽  
Author(s):  
Hanan H. Abd-Elhafeez ◽  
Doaa M. Mokhtar ◽  
Ahmed H.S. Hassan
Keyword(s):  
Close Contact ◽  
Intercellular Junctions ◽  
Secretory Activity ◽  
Treated Group ◽  
Control Group ◽  
Secretory Vesicles ◽  
Melatonin Treatment ◽  
Secretory Structures ◽  
Strong Reaction ◽  
Nonbreeding Season

Telocytes (TCs) are a special type of interstitial cell with characteristic cellular processes that are described in many organs. The current study aimed to investigate TCs in seminal vesicles of the Soay ram responding to melatonin treatment during the nonbreeding season by conventional immunohistochemical stains, and to detect the ultrastructural and morphometrical changes of TCs. TCs in the control group showed a broad range of staining affinity and also reacted positively to CD117/c-kit, CD34, desmin, S-100 protein, and progesterone and estrogen receptors alpha, while after melatonin treatment a strong reaction against these 6 antibodies was recorded. Electron microscopically, TCs in the control group were characterized by a small cell body with distinct long cytoplasmic extensions called telopodes (Tps). Tps had alternation of the thin segment (podomers) and dilated segments (podoms), in which the latter accommodate mitochondria, rough endoplasmic reticulum and caveolae. TCs and their Tps were interconnected by homo- and heterocellular junctions and form a wide network to communicate between different cell types. Tps showed close contact with immune cells, progenitor stem cells, smooth muscle cells and other interstitial cells. Melatonin caused a significant increase in the number of TCs, length of Tps, and number and diameter of secretory vesicles. Also, the melatonin-treated group showed exaggerated secretory activity in the form of a massive release of secretory vesicles from Tps. Moreover, Tps showed an increase in their contact with blood and lymphatic capillaries, nerve endings and Schwann cells. In addition, the shedding of secretory structures (exosomes, ectosomes, and multivesicular bodies) was greater from Tps, which were involved in paracrine signaling in the melatonin-treated group. The length and ramifications of Tps together with the intercellular junctions and the releasing of shed vesicles or exosomes assumed an essential role of TCs in intercellular signaling and coordination. On the basis of their distribution and morphology, we investigated whether the different locations of TCs could be associated with different roles.

Winter coexistence of voles in spruce forest: relevance of seasonal changes in aggression

1975 ◽  
Vol 53 (8) ◽  
pp. 1004-1011 ◽  
Author(s):  
Brian N. Turner ◽  
Michael R. Perrin ◽  
Stuart L. Iverson
Keyword(s):  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Breeding Period ◽  
Spruce Forest ◽  
Vole Population ◽  
Reproductive Condition ◽  
Interspecific Aggression ◽  
Meadow Voles ◽  
Nonbreeding Season ◽  
Short Period

Beginning in November 1973, numerous meadow voles (Microtus pennsylvanicus) moved onto a spruce forest grid occupied by red-backed voles (Clethrionomys gapperi). A resident meadow vole population resulted, the two species coexisting until April 1974, when most meadow voles disappeared from the grid during a relatively short period. Interspecific aggression levels, as determined from voles temporarily removed from the populations and tested in paired encounters in a laboratory arena, were low during the winter, but increased when males of both species entered reproductive condition in the spring. Microtus was generally dominant in early breeding period encounters, but this dominance declined concurrently with the meadow voles' disappearance from the forest. It is argued that meadow voles did not leave the forest to breed, or because the snow cover melted, since this species will live and reproduce in forest in the absence of Clethrionomys. The results are interpreted as support for an earlier hypothesis that competitive habitat exclusion varies seasonally with reproduction-related aggression. Thus, these species apparently may coexist in either of their preferred habitats when interspecific aggression is low (the nonbreeding season), but this relationship terminates when interspecific aggression levels increase with the resumption of breeding in the spring.

scholarly journals Spatially different annual cycles but similar haemosporidian infections in distant populations of collared sand martins

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Steffen Hahn ◽  
Martins Briedis ◽  
Christos Barboutis ◽  
Raffaella Schmid ◽  
Martin Schulze ◽  
...  
Keyword(s):  
West Africa ◽  
Chronic Infection ◽  
Blood Parasite ◽  
Spring Migration ◽  
Lake Chad ◽  
Annual Cycles ◽  
Nonbreeding Season ◽  
Breeding Populations ◽  
High Parasitaemia ◽  
Western Palaearctic

Abstract Background Populations of long-distance migratory birds experience different environments and are consequently exposed to different parasites throughout their annual cycles. Though, specific whereabouts and accompanied host-parasite interactions remain unknown for most migratory passerines. Collared sand martins (Riparia riparia) breeding in the western Palaearctic spend the nonbreeding period in Africa, but it is not yet clear whether specific populations differ in overwintering locations and whether these also result in varying infections with vector-transmitted endoparasites. Results Geolocator tracking revealed that collared sand martins from northern-central and central-eastern Europe migrate to distant nonbreeding sites in West Africa and the Lake Chad basin in central Africa, respectively. While the ranges of these populations were clearly separated throughout the year, they consistently spent up to 60% of the annual cycle in Africa. Ambient light recorded by geolocators further indicated unsheltered roosting during the nonbreeding season in Africa compared to the breeding season in Europe. We found 5–26% prevalence of haemosporidian parasites in three breeding populations and one migratory passage population that was only sampled but not tracked. In total, we identified seven Plasmodium and nine Haemoproteus lineages (incl. two and seven new lineages, respectively), the latter presumably typical for swallows (Hirundinae) hosts. 99.5% of infections had a low intensity, typical for chronic infection stages, whereas three individuals (0.5%) showed high parasitaemia typical for acute infections during spring migration and breeding. Conclusions Our study shows that blood parasite infections are common in several western Palaearctic breeding populations of collared sand martins who spent the nonbreeding season in West Africa and the lake Chad region. Due to long residency at the nonbreeding grounds blood parasite transmissions may mainly occur at host population-specific residences sites in Europe and Africa; the latter being likely facilitated by unsheltered roosting and thus high vulnerability to hematophagous insects. The rare cases of high parasitaemia during spring migration and breeding further indicates either relapses of chronic infection or primary infections which occurred shortly before migration and during breeding.

scholarly journals Biometrics of Razorbills Alca torda staying during the nonbreeding season in the Polish Baltic zone

Ornis Svecica ◽  
2013 ◽  
Vol 23 (3–4) ◽  
pp. 159-163
Author(s):  
Włodzimierz Meissner ◽  
Joanna Drozdowska ◽  
Szymon Bzoma
Keyword(s):  
Baltic Sea ◽  
Wing Length ◽  
Breeding Population ◽  
Breeding Period ◽  
Clinal Variation ◽  
The Baltic Sea ◽  
Final Size ◽  
Alca Torda ◽  
Nonbreeding Season ◽  
The Baltic

Biometrical analysis of Razorbills Alca torda captured or drowned in fishing nets in the Polish economic zone of the Baltic Sea is based on measurements of 98 individuals collected in the non-breeding period (October–April) in 2006–2013. These birds are assumed to represent the breeding population of the Baltic Sea as recoveries show that very few other birds visit that area. Bill depth and wing length of juveniles were much smaller than in older birds which suggests that the final size of these measurements is not achieved during the first winter but continue to increase as the birds grow older. In older birds only total head length and bill length were significantly larger in males than in females. Mean bill depth of Razorbills from the Polish Baltic zone fits well to clinal variation from south-west to north of the European part of the breeding range. However, mean wing length was much larger than expected according to the regression, which might result from differences in measuring technique. On the other hand it cannot be excluded that the Baltic population may actually have longer wings.

Mercury levels and health parameters in the threatened Olrog’s Gull (Larus atlanticus) from Argentina

2010 ◽  
Vol 181 (1-4) ◽  
pp. 1-11 ◽  
Author(s):  
Luciano Francisco La Sala ◽  
Pablo Fabricio Petracci ◽  
Judit Emmy Smits ◽  
Sandra Botté ◽  
Robert W. Furness
Keyword(s):  
Olrog’S Gull ◽  
Health Parameters

Epidemiology of acanthocephalan infections in crabs from the Bahía Blanca Estuary, Argentina

2011 ◽  
Vol 86 (4) ◽  
pp. 446-452 ◽  
Author(s):  
L.F. La Sala ◽  
A.M. Perez ◽  
S.R. Martorelli
Keyword(s):  
Risk Factors ◽  
Carapace Length ◽  
Carapace Width ◽  
Infection Prevalence ◽  
Intensity Of Infection ◽  
Breeding Colony ◽  
Bahía Blanca Estuary ◽  
Feeding Area ◽  
Olrog’S Gull ◽  
Blanca Estuary

AbstractThis study was conducted in two populations of crabs, Cyrtograpsus angulatus and Neohelice granulata from the Bahía Blanca Estuary, in Argentina, to identify risk factors for infection by the acanthocephalan Profilicollis chasmagnathi and to assess the association between infection and mortality of these hosts. Cyrtograpsus angulatus and N. granulata crabs were sampled seasonally over the course of a year, and spring sampling included collection of dead crabs predated by Olrog's gulls in a nearby breeding colony. Potential risk factors for infection were assessed and the number of cystacanth larvae per crab was counted. In C. angulatus, the odds of infection increased by 7% for each millimetre increase in carapace length, and were nearly 17 times greater in crabs sampled from the Olrog's gull feeding area compared with those sampled from nests in the breeding colony. For every millimetre increase in carapace length in N. granulata, the odds of infection increased by 13% in crabs from the breeding colony, and by 32% in crabs from the feeding area. Mean intensity of infection in N. granulata increased by 16.5% for each additional millimetre of carapace width. The level of parasite aggregation was lowest in the largest C. angulatus and highest in N. granulata predated by Olrog's gull. The results show that host size is the most important factor influencing infection prevalence in both crab species and intensity of infection in N. granulata, and suggest the presence of parasite-induced mortality in the populations studied.

Seasonal reproduction in the highveld mole-rat, Cryptomys hottentotus pretoriae (Rodentia: Bathyergidae)

2002 ◽  
Vol 80 (5) ◽  
pp. 810-820 ◽  
Author(s):  
L Janse van Rensburg ◽  
N C Bennett ◽  
M van der Merwe ◽  
A S Schoeman
Keyword(s):  
Body Mass ◽  
Reproductive Tract ◽  
Plasma Testosterone ◽  
Breeding Period ◽  
Corpora Lutea ◽  
Seasonal Breeding ◽  
Nonbreeding Season ◽  
Ovarian Histology ◽  
Mole Rat ◽  
Reproductive Females

The highveld mole-rat, Cryptomys hottentotus pretoriae, is a cooperatively breeding rodent that exhibits seasonal breeding and a reproductive division of labour. Body mass, reproductive-tract morphometrics, ovarian histology, and plasma oestrogen and progesterone concentrations were studied for both reproductive and non-reproductive females from 55 colonies, the main objective being to determine the inclination of this species towards seasonal breeding. Offspring are born from July through to November. However, qualitative analysis of ovarian histology revealed that reproductive females retain the potential for ovulation and subsequent production of corpora lutea during the late-summer nonbreeding period (December–March). Seasonal differences were found in ovarian morphometrics and hormone concentrations that are associated with enhanced follicular activation in April and May and subsequent conceptions from July through to November during the breeding period. The nonbreeding period coincides with maximal dispersal opportunities in the summer-rainfall areas inhabited by the highveld mole-rat. Body mass, reproductive-tract morphometrics, testicular histology, and plasma testosterone concentrations were determined for reproductive and non-reproductive males from 37 colonies. Available evidence suggests that there is a gradual increase in testicular mass for reproductive males as the breeding season approaches, but after September the testicular parameters fall. Seminiferous-tubule diameter was significantly greater in reproductive males but exhibited no seasonal variation. Testosterone concentrations were higher in reproductive males. Current data support a lack of gonadal regression in males during the nonbreeding season.

Sign in / Sign up

Export Citation Format

Share Document