scholarly journals Social organisation of the northern giant mouse lemur Mirza zaza in Sahamalaza, north western Madagascar, inferred from nest group composition and genetic relatedness

2013 ◽  
Vol 82 (2) ◽  
pp. 71-83 ◽  
Author(s):  
E. Johanna Rode ◽  
K. Anne-Isola Nekaris ◽  
Matthias Markolf ◽  
Susanne Schliehe-Diecks ◽  
Melanie Seiler ◽  
...  

Shelters such as leaf nests, tree holes or vegetation tangles play a crucial role in the life of many nocturnal mammals. While information about characteristics and availability of these resources may help in conservation planning, nest use gives an indication about a species’ social organisation. The northern giant mouse lemur (Mirza zaza) is threatened by habitat loss within its restricted range. Our aim was to examine nest site preferences of M. zaza and to explore the species’ social organisation by examining sleeping site aggregation size and genetic relatedness within and between such aggregations. In the Ankarafa Forest inside Sahamalaza – Iles Radama National Park, northwestern Madagascar, we radio-tagged five male and three female M. zaza and followed them for 2.5 months during the dry season. We identified sleeping trees and observed animals during emergence in the evening and return in the morning. We compared sleeping trees and microhabitats around nest sites to trees and habitat used during nightly activity and to random sites. We found that nests were well covered by canopy, even during the dry season, and were located near the tree trunk a few meters below the tree top. Nest sites were characterised by large (> 30 cm DBH) and tall trees (>16 m) with many lianas. Up to four animals shared one to three group-exclusive nests for up to 50 days. Two of the nest groups included two and three males with fully developed testes. Relatedness data revealed that the adult males sharing nests were either unrelated or closely related. These data suggest that M. zaza is sleeping in social nest groups including multiple males, which is unusual among nocturnal strepsirrhines. Apart from protecting suitable sleeping trees and discouraging selective logging of large trees, we recommend conducting further studies on the species’ social organisation throughout an entire season.

1926 ◽  
Vol 17 (2) ◽  
pp. 183-187 ◽  
Author(s):  
Lawrence H. Dunn

An investigation of the breeding habits of the yellow fever mosquito, Aëdes aegypti, Linn., in West Africa was begun in December 1925. This was undertaken for the purpose of ascertaining if the selection of breeding-places of this mosquito in Africa differs from that in the Western Hemisphere, and, if so, to learn if this difference is sufficient to be of material importance in yellow fever control work.Since it was believed that breeding in tree-holes constituted a problem worthy of investigation, it was decided to make a survey of the rot-holes and fork-hollows in trees in the vicinity of Lagos, in the Southern Province of Nigeria. This survey was begun on 8th December 1925, shortly after the rainy season had passed and the dry season had set in. However, after inspecting a number of trees, the fact became evident that this was not a propitious time of the year for finding larvae in such places, since practically all of the holes were without water, and their contents, consisting of leaves and débris, were dry.This early drying of the material in the holes drew my attention to the probability of mosquito eggs remaining in the holes, surviving the drought of the dry season and producing larvae with the beginning of the rains. In furtherance of this question, an examination of the dry holes was then began, and material collected from all those that were suitable. The term “ suitable ” in this sense signifies that the hole was in a living tree—of a formation to contain water, for a short time at least—that the aperture was of sufficient size to allow the débris to be removed and the inside of the hole scraped, and that the contents were dry. The distance of the trees from habitations, their location in open areas or thick bush, the height of the holes from the ground, the exposure of the holes to the sun, or the amount of débris contained caused no discrimination to be made.


1980 ◽  
Vol 7 (1) ◽  
pp. 103 ◽  
Author(s):  
ST Garnett

A population of dusky moorhens was studied between October 1974 and December 1976. Moorhens were present in the study area throughout the year, existing predominantly in free-ranging flocks in May and June and tending to form territorial groups of from two to seven birds from July to April. In a group there were from one to three males per female; all males copulated with all females. Groups formed in July were predominantly of experienced adults and did not cease territoriality until April; those formed later, in September, were predominantly of immatures and tended to cease territoriality in March. The former had larger territories with more reeds, less sexual behaviour although more frequent successful coition, and a higher productivity than the latter. Productivity did not increase with group size although those with more than four birds lost twice as many eggs as smaller groups. It is unlikely that members of a group are related. The most frequent group size was four and it is postulated that groups of this size produce the most young. The skewed ratio in groups may result from the scarcity of nest sites, which limits the number of females per group.


1986 ◽  
Vol 13 (3) ◽  
pp. 461 ◽  
Author(s):  
FHJ Crome

Nest sites of waterfowl (pacific black duck, grey teal, pink-eared duck, maned duck and Australian shelduck) in 200 tree holes were monitored monthly over 4 years in a swamp complex near Booligal, N.S.W. The most nests occurred in 1978 following a complete drawdown and reflooding of the swamps. A rising water level on an already full swamp did not result in significant nesting activity. The response to the drawdown and filling was not a simple matter of more aquatic vegetation and invertebrates being produced at this time. Samples of nekton were taken by net and quadrats, and plankton was taken by nets. The results indicated that there were more of the common invertebrates in other seasons than in that following the filling, and vegetation did not develop fully until the 1978 breeding season was nearly finished. It is postulated that the high nesting activity related to a massive production of invertebrate detritivores, particularly Chironomus tepperi, which was stimulated by the decaying organic material from the dead aquatic vegetation (e.g. Vallisneria spiralis, Carex sp., Elaeochoris sp. and algae) of the previous full period, and the flooded dead dryland vegetation (e.g. grasses). A lack of these chironomids is suggested as the cause of the low nesting rates in other seasons, when the swamps were full and food apparently was available. It is also postulated that these and other detritivores are efficiently captured and provide a superabundant food source, at the water surface and in very shallow water, for both adults and chicks. Other invertebrates are either not available to chicks in these microhabitats or are harvested too inefficiently or slowly by adults. The concept that a rising water level per se is central to the breeding ecology of some species of ducks should be abandoned. Rather, the significant phenomena are the drawdown, and the production of detritus and detritivorous invertebrates when the wetland basin is refilled.


1989 ◽  
Vol 37 (6) ◽  
pp. 627 ◽  
Author(s):  
C Kemper ◽  
DJ Kitchener ◽  
WF Humphreys ◽  
RA How ◽  
LH Schmitt ◽  
...  

Breeding, population dynamics and seasonal changes in physical and physiological parameters were examined in Isoodon macrourus at the Mitchell Plateau between September 1981 and November 1982. Females gave birth to litters of 2.5 � 1.0 (16) young between September and April. They produced up to three litters in a breeding season with an average interval between successive litters of 89.5 (51-108) days. Adult testosterone levels and scrota1 size began to increase in July and peaked in September 1982. The overall ratio of adult males to adult females was 1:0.54; it was 1:0.80 for pouch young. Females were more frequently trapped on sequential trips than were males. Density on the grids increased towards the end of the dry season (July and September 1982)-mostly as a result of increased numbers of females. Adult males and females moving onto the grids during the dry season tended to select different habitats. Adult males moved significantly more in the wet season (September 1981, January and April) than they did in the dry season (July and September 1982); they also moved significantly more than adult females in the wet season. Seasonal variations were recorded for most physical and physiological parameters. During the wet period from September 1981 to January 1982, body weight, haemoglobin, haematocrit and total plasma albumin declined, while total white blood cells and proportion of lymphocytes to granular leucocytes rose. This indicated that this period was one of change in condition for this species. Compared to adult females, adult males were larger and heavier, had higher values of haematocrit and lymphocytes, and lower values of granular leucocytes, free steroids, CBGBd and albumin bound corticosteroid. There was considerable between-year variability in condition of individuals and both sexes differed significantly in September 1981 and 1982 in their weight, haematocrit, total white blood cells, granular leucocytes, MCBC and testosterone. Individuals at disparate localities at the Mitchell Plateau showed similar seasonal physiological and physical responses, except for one grid where they were heavier.


1999 ◽  
Vol 14 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Dayna M. Ayers ◽  
Donald J. Bedunah ◽  
Michael G. Harrington

Abstract In many western Montana ponderosa pine (Pinus ponderosa) stands, fire suppression and past selective logging of large trees have resulted in conditions favoring succession to dense stands of shade-tolerant, but insect- and disease-prone Douglas-fir (Pseudotsuga menziesii). Stand thinning and understory prescribed burning have been proposed as surrogates for pre-Euro-American settlement ecological processes and as potential treatments to improve declining forest condition and reduce the probability of severe wildfire. To test the effectiveness of these silvicultural techniques on overstory and understory conditions, research is ongoing in the Lick Creek Demonstration Site in the Bitterroot National Forest, Montana. Our research examined the response (mortality and vigor) of the dominant browse species, antelope bitterbrush (Purshia tridentata) and Scouler's willow (Salix scouleriana), to a ponderosa pine stand restoration project utilizing four treatments: (1) a shelterwood cut that removed 53% of the tree basal area; (2) a shelterwood cut with a low fuel consumption burn; (3) a shelterwood cut with a high fuel consumption burn; and (4) a control. Prior to the application of treatments, 1,856 bitterbrush and 871 willow were located, and their survival and vigor subsequently monitored for 2 yr posttreatment. The cut and burn treatments resulted in the greatest reduction in antelope bitterbrush and Scouler's willow density averaging 66% and 24% of pretreatment density, respectively. The shelterwood cut reduced bitterbrush and Scouler's willow density by 35% and 14%, respectively. On treatments receiving a shelterwood cut (all treatments but the control), but where antelope bitterbrush and Scouler's willow did not have fire damage, mortality was 45% for bitterbrush and 20% for willow, respectively. For bitterbrush and Scouler's willow plants that received fire damage, mortality was 72% for bitterbrush and 19% for willow. Although the burn and shelterwood harvest treatments resulted in reduced density of antelope bitterbrush and Scouler's willow 2 yr posttreatment, these treatments increased vigor of both species and created mineral seedbeds that may be necessary for establishment of seedlings. West. J. Appl. For. 14(3):137-143.


2014 ◽  
Vol 318 ◽  
pp. 103-109 ◽  
Author(s):  
Plinio Sist ◽  
Lucas Mazzei ◽  
Lilian Blanc ◽  
Ervan Rutishauser

Behaviour ◽  
1992 ◽  
Vol 121 (1-2) ◽  
pp. 61-93 ◽  
Author(s):  
Fernando Colmenares

AbstractThree features of the hamadryas society, Papio hamadryas, which are quite unique among Old World monkeys, are its multileveled structure (i.e. harems, clans, bands, troop), the reported pattern of female dispersal (i.e. males tend to remain in their natal clans whereas females tend to move between clans and bands), and the special bonds that develop between adult males. It has also been hypothesized that the males of a clan are genetically related. In this paper a causal approach is adopted in order to investigate the proximate factors which can account for the structure/dynamics of socio-spatial group organization observed over two years in a large colony of hamadryas and hybrid baboons housed in an outdoor enclosure in the Madrid Zoo, containing 18 adult males with known kin relations. I first examined the types of grouping observed in the colony and the alternative social strategies used by the different male individuals during their ontogenetic trajectories for acquiring, and maintaining, females. Since the hamadryas baboon is considered a female-transfer species, I studied whether the sex that stays, that is, the males, developed some kind of mutual affiliative relationship, as one would predict, and whether their inter-male bonding preferences were based on genetic relatedness or on familiarity (i.e. sharing the same developmental environment during socialization).


1961 ◽  
Vol 51 (4) ◽  
pp. 705-713 ◽  
Author(s):  
J. P. Glasgow ◽  
E. Bursell

A population of Glossina swynnertoni Aust., at Shinyanga, Tanganyika, has been studied in respect of size and fat content of non-teneral males by monthly samples over a period of 13 years.Flies are large from February to July and small from August to January, and this change in size suggests an effect of the wet season (December to May) and dry season (June to November) upon the parent females, allowing for the time-lag of two months representing pupal development and mean age of adult males at capture. Male flies have more fat in the rains and less in the dry season and it is possible that similar changes in the nutritional status of females are responsible for the observed size changes.The correlation found in earlier work between the size of male flies in any month and saturation deficit two months earlier is confirmed, but reasons are given for rejecting a simple causal interpretation of this correlation.Since 1951, there has been a progressive decrease in size of G. swynnertoni in the area studied, more especially as regards those produced in the dry season.


1993 ◽  
Vol 57 (2) ◽  
pp. 199-209 ◽  
Author(s):  
J. E. O. Rege ◽  
R. R. von Kaufmann ◽  
R. I. Mani

AbstractA study urns conducted to examine herd structures and cattle disposal patterns of Bunaji herds kept under traditional management at four locations in the subhumid zone of Nigeria. Sale for meat was the single most important disposal reason, accounting for proportionately 0·55 of all disposals. Mean age of cattle sold for meat was 8 years but the age range was wide: animals as old as 17·4 years were involved in such sales. Male animals were sold at a younger age (6·2 years) than females (9·3 years). Sale of calves was an important exit avenue for rural herds with less access to milk market. Calves were sold at a mean age of 1·1 years and male calves accounted for a larger proportion (0·62) of such sales. Animal sales were highest in the early dry season and lowest in the early wet season. The predominantly arable farming location, Ganawuri, had the highest frequency of animal sales and lowest frequency of exits for ‘social functions’ (exchanges, transfers and gifts). Animal transfers, gifts and exchanges were important disposal routes in the traditionally pastoral communities, especially in locations with good grazing (e.g. Abet). Exits involving exchanges, transfers and gifts were more frequent during the dry season and least frequent in the wet season. An average herd had 77 head of cattle composed proportionately of 0·54 adult females (>3 years), 0·13 adult males (>3 years), 0·08 young bulls (1 to 3 years), 0·13 heifers (1 to 3 years) and 0·11 calves (0 to 1 year). There was a tendency toward smaller herds in later years (97 in 1980 to 51 in 1989) and a decrease in the ratio of adult females to males (from 6:1 in 1980 to 3:1 in 1989). Substantial between-location differences existed in herd size ami herd structure, ranging from the ‘beef orientation’ of the arable Ganawuri with a high proportion of immatures and calves, to the pastoral situation in Abet and Kurmin Biri with high proportion of adult animals. The proportions of adults were lowest in the early dry season, reflecting seasonal pattern in disposal and calving. The pattern in disposal reasons over time indicated a decrease in the proportion of animals exiting herds through exchanges, transfers and gifts and signified a possible shift from tradition, probably a response to population pressures and emergence of cash economies.


1993 ◽  
Vol 20 (4) ◽  
pp. 405 ◽  
Author(s):  
TM Bubela ◽  
DCD Happold

Mastacomys fuscus is a grass-eating rodent of south-eastern Australia that lives mainly in subalpine habitats where snow covers the ground for about four months of the year. Radiotelemetry revealed that in summer the females were territorial. Home ranges of males were larger than those of females and overlapped extensively with the home ranges of other males and with the home ranges of up to three females. In winter, males and females huddled together in communal nests. The locations of nest sites, cover, water and grass also determined the spatial organisation of individuals. The evidence suggests that M. fuscus is not monogamous, but there were insufficient data to determine whether polygyny or promiscuity is the preferred mating system. The social organisation of this species, solitary in summer and communal in winter, is a response to the cold snowy winters and the limited time for reproduction in summer. The social organisation of M, fuscus is different from that of the other conilurine rodents of Australia, but similar to that of rodents that live in other alpine regions of the world.


Sign in / Sign up

Export Citation Format

Share Document