Migration, overwintering, and reproductive patterns of Taricha granulosa on southern Vancouver Island

1974 ◽  
Vol 52 (4) ◽  
pp. 541-545 ◽  
Author(s):  
M. G. Oliver ◽  
H. M. McCurdy

Sexual dichotomy in habitat selection during the nonbreeding season was studied in the rough-skinned newt Taricha granulosa from November 1970 to August 1973 on southern Vancouver Island. Field results show that in this area adult females normally migrate from breeding ponds to overwinter on land. Adult males normally remain permanently aquatic. Related observations on the reproductive cycle of T. granulosa show that females, who lay their eggs singly, deposit them for a period of a few days, followed by a period of nonegglaying. This process is repeated at intervals. Oviposition can occur from late April to July in this area. Females who were induced to ovulate in the laboratory each deposited three eggs per day for 5 days before opposition ceased. Thus the reproductive cycles of field and taboratory-acclimated females are correlated.

2006 ◽  
Vol 27 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Nora Ibargüengoytía ◽  
Jorgelina Boretto

AbstractThis paper studies minimum SVL at sexual maturity, sexual dimorphism, operational sex ratio, male and female reproductive cycles, and litter size of viviparous Phymaturus antofagastensis, a species living at high altitude in the temperate climate of Catamarca, Argentina. Males reached sexual maturity at 90 mm, and females at 79 mm. Adult males attained significantly larger body size and head width than adult females. Histological analysis showed asynchrony in spermatogenesis timing among males and spermatozoa storage in epididymis throughout the reproductive season (spring to early autumn). Females showed a biennial reproductive cycle taking at least one activity season to perform either vitellogenesis or pregnancy. Brood size resulted in two offspring, a condition similar to other species of the genus, with births occurring in late summer. The reproductive cycle of Phymaturus antofagastensis shows a new response in males and females to harsh environments characterized by short activity seasons, long hibernation periods and large daily and seasonal thermal fluctuations.


2012 ◽  
Vol 70 (1) ◽  
pp. 173-185 ◽  
Author(s):  
Julie M. Andersen ◽  
Yolanda F. Wiersma ◽  
Garry B. Stenson ◽  
Mike O. Hammill ◽  
Aqqalu Rosing-Asvid ◽  
...  

Abstract Andersen, J. M., Wiersma, Y. F., Stenson, G. B., Hammill, M. O., Rosing-Asvid, A., and Skern-Maurizen, M. 2013. Habitat selection by hooded seals (Cystophora cristata) in the Northwest Atlantic Ocean. – ICES Journal of Marine Science, 70:173–185. We examined annual habitat use for 65 hooded seals (32 adult females, 17 adult males, and 16 juveniles) equipped with satellite relay data loggers (SRDLs) in spring or summer during five field seasons (2004–2008). A combined approach using first passage time (FPT) analysis and a generalized additive model (GAM) was applied to test for habitat selection, with a focus on environmental parameters of depth, slope, ice, sea surface temperature (SST), and chlorophyll. The models were run on adult males, adult females, and juveniles separately, and the results identified SST, depth, and chlorophyll as the most important factors influencing habitat selection across all categories. Furthermore, males and females preferred similar habitat conditions, but were separated geographically, and by depth, at various times of the year. Males appeared to be more localized in their habitat use patterns, focusing their search effort in areas of complex seabed relief such as Baffin Bay, Davis Strait, and the Flemish cap, while females concentrated their search effort along shelf areas (e.g. the Labrador shelf). These findings support our hypothesis that hooded seals prefer areas where topography and oceanographic processes create favourable foraging conditions.


1984 ◽  
Vol 116 (6) ◽  
pp. 785-793 ◽  
Author(s):  
C. David Rollo ◽  
Marvin W. Gunderman

AbstractLong term daily feeding in individual adult males and females of Periplaneta americana (L.) was quantified using a standardized diet. There was considerable variation among days, probably related to digestive processes with a period greater than 1 day. Female feeding was correlated with the reproductive cycle, most feeding occurring during the first few days after depositing an oötheca. Females differed with respect to the length of their reproductive cycles, and the amount of food that was accumulated prior to producing an oötheca. Females with high feeding rates produced oöthecae at a faster rate, but they were less efficient at converting food into oöthecal biomass than females that ate more slowly. A decrease in temperature from 25 °C to 20 °C more than doubled the length of the reproductive cycle, but the amount of food accumulated during inter-ovipositional intervals and the size of the oöthecae were not affected.


Zootaxa ◽  
2011 ◽  
Vol 2983 (1) ◽  
pp. 39 ◽  
Author(s):  
IVAN L. F. MAGALHÃES ◽  
ADALBERTO J. SANTOS

In this paper, M. yanomami n. sp., from Brazilian Amazonia, Chaetacis bandeirante n. sp., from Central Brazil, and the males of M. gaujoni Simon, 1897 and M. ruschii (Mello-Leitão, 1945) n. comb. , respectively from Ecuador and Brazil, are described and illustrated for the first time. An ontogenetic series of the last development stages of both sexes of Micrathena excavata (C. L. Koch, 1836) is illustrated and briefly described. Adult females are larger and have longer legs and larger abdomens than adult males. Probably females undergo at least one additional moult before adulthood, compared to males. Micrathena ornata Mello-Leitão, 1932 is considered a junior synonym of M. plana (C. L. Koch, 1836), and M. mastonota Mello-Leitão 1940 is synonymized with M. horrida (Taczanowski, 1873). Acrosoma ruschii Mello-Leitão, 1945 is revalidated, transferred to Micrathena and considered a senior synonym of M. cicuta Gonzaga & Santos, 2004. Chaetacis necopinata (Chickering, 1960) is recorded for Brazil for the first time. Chaetacis incisa (Walckenaer, 1841) is considered a nomen dubium.


1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.


Behaviour ◽  
1980 ◽  
Vol 72 (1-2) ◽  
pp. 26-48 ◽  
Author(s):  
Patrick Duncan

AbstractTime-budgets of adult and weaned sub-adult horses were studied in a small population of Camargue horses living in semi-liberty. The categories of activities used were: Standing resting, Lying flat, Lying up, Standing alert, Walking, Trotting, Galloping, Rolling and Foraging. The main differences in time-budgets were related to age and to sex : young horses spent more time lying (sleeping), males spent more time standing alert and in rapid movements (trot, gallop), while usually foraging less than did the adult females. During the three years of the study the population increased from 20 to 54 horses and there were considerable changes in social structure as the number of adult males increased. Associated with these developments there were some changes between years in the time-budgets: the most striking of which was a general trend for all horses to spend less time lying. Nonetheless the time-budgets showed a considerable constancy across years and age/sex-classes, especially with regard to time spent foraging. This conclusion may provide a clue as to why horses have an unusual social system based on long term relationships between a male and the females of his harem.


1991 ◽  
Vol 21 (9) ◽  
pp. 1360-1364 ◽  
Author(s):  
Y. A. El-Kassaby ◽  
J. Maze ◽  
D. A. MacLeod ◽  
S. Banerjee

In 1987, a study was initiated to determine the properties of seed from apparently premature cones of yellow-cedar (Chamaecyparisnootkatensis (D. Don) Spach) on southwestern Vancouver Island. After pollination with fresh pollen in February, all cones showed signs of maturation (i.e., drying and shedding) by December. Samples of these 1-year-old cones were collected for seed extraction and germination tests. Germination ranged between 10 and 42% for isolated cones (i.e., bagged) and between 0 and 25% for unisolated cones. Similar germination results were obtained for the 1988 and 1989 cone crops. Anatomical observations revealed that the 10-month-old embryos were similar in both size and shape to embryos from 2-year-old seeds. It was concluded that transplanting yellow-cedar trees to warmer, low-elevation sites enabled seed cones to continue development without significant delay caused by dormancy induced by cold temperatures at higher elevations. This alteration of normal phenology reflects the impact of environmental contingencies on development.


2006 ◽  
Vol 2 (3) ◽  
pp. 337-340 ◽  
Author(s):  
Beth A Hahn ◽  
Emily D Silverman

For migratory songbirds nesting in northern temperate forests, a short breeding season demands that males rapidly establish territories. Because critical insect and vegetation resources are unavailable during spring arrival, we suggest that conspecifics serve as settlement cues for males new to a local population. To test conspecific attraction, we conducted playback experiments with American redstarts Setophaga ruticilla . Experimental results demonstrate that song playbacks strongly attract conspecifics, recruiting an average of 4.2 additional males per plot; adult males new to our sites increased, while yearling males failed to respond. Yearlings arrived 6 to 10 days later than adults, raising the possibility that yearlings responded to songs of early arriving adults rather than to playbacks. Our work indicates that conspecific attraction is an important mechanism for breeding habitat selection in an established population of a migratory forest songbird, but the effect is moderated by age, reproductive experience and arrival timing.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Paul J. Ode ◽  
Dhaval K. Vyas ◽  
Jeffrey A. Harvey

The diverse ecology of parasitoids is shaped by extrinsic competition, i.e., exploitative or interference competition among adult females and males for hosts and mates. Adult females use an array of morphological, chemical, and behavioral mechanisms to engage in competition that may be either intra- or interspecific. Weaker competitors are often excluded or, if they persist, use alternate host habitats, host developmental stages, or host species. Competition among adult males for mates is almost exclusively intraspecific and involves visual displays, chemical signals, and even physical combat. Extrinsic competition influences community structure through its role in competitive displacement and apparent competition. Finally, anthropogenic changes such as habitat loss and fragmentation, invasive species, pollutants, and climate change result in phenological mismatches and range expansions within host–parasitoid communities with consequent changes to the strength of competitive interactions. Such changes have important ramifications not only for the success of managed agroecosystems, but also for natural ecosystem functioning. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.


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