scholarly journals Nesting With The Wasp Ropalidia Cincta Increases Nest Success of Red-Cheeked Cordonbleu (Uraeginthus Bengalus) in Ghana

The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1022-1037 ◽  
Author(s):  
Paul Beier ◽  
Agba Issahaku Tungbani
Keyword(s):  
Reproductive Success ◽  
Nest Predation ◽  
Northern Ghana ◽  
Social Hymenoptera ◽  
Tropical Regions ◽  
Nest Sites ◽  
Wasp Nests ◽  
Habitat Feature ◽  
Working Hypotheses ◽  
Rule Out

AbstractAssociations between birds and social Hymenoptera (ants, wasps, bees) are common in tropical regions and are usually assumed to be commensal relationships that benefit birds but neither help nor harm the arthropods. However, benefits to birds have been documented in only four such associations, and no previous research has rigorously investigated costs or benefits to associated hymenopterans. We followed the nesting cycles of an estrildid finch, the Red-cheeked Cordonbleu (Uraeginthus bengalus), and a common nesting associate, the wasp Ropalidia cincta, during 2002 and 2003 in northern Ghana to compare reproductive success of birds and wasps nesting in association with that of birds and wasps nesting separately. Red-cheeked Cordonbleus and wasps nested together in the same tree 3.7 × as often as expected if nesting decisions were made independently, with 74% of bird nests and 74% of wasp colonies occurring in associations. Bird nesting was initiated ≈33 days after founding of an associated wasp colony; bird nests and wasp colonies were, on average, 42 cm apart. In both years, Red-cheeked Cordonbleus in nesting associations with wasps were twice as likely to fledge young as birds nesting in trees without wasps. Reduced predation was apparently a major reason for increased fledging success: we documented four cases of nest predation on 122 Red-cheeked Cordonbleu nests associated with wasps, and 11 cases on 90 nests not associated with wasps. Association with birds did not affect the success of wasp colonies. Although our observational study cannot rule out the possibility that both species coincidentally shared a preference for a habitat feature in limited supply, suitable nest sites did not appear to be limiting (74% of potential nest trees had neither bird nor wasp nests). Reproductive success of Red-cheeked Cordonbleu populations in this region may be limited by the number of available wasp colonies. By designing our study to address four working hypotheses (commensalism, mutualism, parasitism, coincidence of habitat preference), we have provided strong evidence that this relationship is commensal.Augmentation du Succès de Nidification de Uraeginthus bengalus Nichant avec des Guêpes Ropalidia cincta au Ghana

Reproductive Success and Nest Predation in the Superb Lyrebird, Menura superba

1980 ◽  
Vol 7 (2) ◽  
pp. 271 ◽  
Author(s):  
a Lill
Keyword(s):  
Reproductive Success ◽  
Breeding Success ◽  
Nest Predation ◽  
Ground Level ◽  
Recruitment Rate ◽  
Circumstantial Evidence ◽  
Above Ground Level ◽  
Breeding Female ◽  
Nest Sites ◽  
Native Birds

Breeding success and nest predation were analysed in two superb lyrebird populations studied over six years. Egg success was estimated at 11-20%, giving an annual recruitment rate of 0.1-0.2 fledglings per breeding female. Predation accounted for at least 79% of nesting mortality and the risk was greater during the nestling phase. Preferred nest sites were 0.6-1.8 m above ground level on earth banks and in trees but were most susceptible to predation. Circumstantial evidence implicated native birds and introduced mammals as the principal nest predators. The generality and evolutionary implications of these findings are discussed.

Coloniality in the Yellow-Rumped Cacique as a Defense against Nest Predators

The Auk ◽  
1985 ◽  
Vol 102 (3) ◽  
pp. 506-519 ◽  
Author(s):  
Scott K. Robinson
Keyword(s):  
Group Size ◽  
Colony Size ◽  
Nest Predation ◽  
Open Water ◽  
Nest Sites ◽  
Avian Predators ◽  
Group Defense ◽  
Wasp Nests ◽  
Nest Predators

Abstract Individuals of the colonial Yellow-rumped Cacique (Cacicus cela) in Amazonian Peru can defend their nests against predators in three ways. First, by nesting on islands and around wasp nests, caciques are safe from arboreal mammals such as primates, which destroy many more-accessible colonies. Caimans and otters that live in lakes also protect island colonies from snakes, which are vulnerable when crossing open water. Second, by clustering nests together and mobbing as a group, caciques can deter many avian predators, which take spatially isolated nests in small colonies. The effectiveness of mobbing increases with group size, which in turn is correlated with colony size. Third, by mixing their enclosed, pouchlike nests with abandoned nests, caciques can hide their nests from some predators. Overall, nests in clusters on islands and around wasp nests suffer the least predation, largely because they are well protected against the cacique's major predators. Females switch colonies after losing nests to a predator, usually to sites that offer protection against that predator. By this mechanism, the best colony sites accumulate the largest numbers of nests. It is unclear, however, why all females do not nest in the safest colony sites. I argue that nest predation favors coloniality because of the scarcity of nest sites that are safe from mammals and the increased effectiveness of group defense.

scholarly journals The Extent of Heat on Health and Sustainable Farming in Ghana –Bawku East

2014 ◽  
Vol 3 (3) ◽  
pp. 56 ◽  
Author(s):  
Frimpong Kwasi ◽  
Jacque Oosthuizen ◽  
Eddie Van Etten
Keyword(s):  
Developing Countries ◽  
Health Effects ◽  
Rural Areas ◽  
High Heat ◽  
Northern Ghana ◽  
Tropical Regions ◽  
Wet Bulb Globe Temperature ◽  
Time Period ◽  
Outdoor Work ◽  
Globe Temperature

<p>Little is known about the health effects of heat in outdoor work and appropriate work and rest schedules for farmers working in developing countries. As temperatures continue to increase in tropical regions, such as Northern Ghana, it is necessary to evaluate how farmers experience and respond to high heat exposures. In this study, WBGT (Wet Bulb Globe Temperature) estimates and the ISO work / rest standards were applied to a cohort of farmers in the rural areas of Bawku East, Northern Ghana, to assess how farmers respond to high heat and how much they rest to protect their health, as well as the level of heat on their productivity. WBGT data was recorded over a period of 6 months among vegetable, cereals, and legume farmers. The ISO proposed and actual rest regimes observed by farmers in the same time period were evaluated. In the dry season the dry bulb temperature rose as high as 45 ºC, while during the humid months of March and April WBGT rose to levels as high as 34 ºC. Farmers worked for nine hours a day during these hot periods with insufficient rest, which has adverse consequences on their health and productivity.</p>

The Breeding System of the Three-Spined Stickleback, Gasterosteus Aculeatus (Forma Leiura) With Reference To Spatial and Temporal Patterns of Nesting Activity

Behaviour ◽  
1993 ◽  
Vol 126 (1-2) ◽  
pp. 97-124 ◽  
Author(s):  
Sechi Mori
Keyword(s):  
Reproductive Success ◽  
Gasterosteus Aculeatus ◽  
Nest Building ◽  
Lifetime Reproductive Success ◽  
Spatial And Temporal Patterns ◽  
Small Stream ◽  
Nest Distribution ◽  
Nest Sites ◽  
Sexual Characteristics ◽  
Individual Success

Abstract1) The breeding succes of three-spined stickleback (Gasterosteus aculeatus L., forma leiura) males in a small stream of the Tsuya River, Gifu Prefecture, Central Japan, was studied with reference to timing of nesting initiation, use of space for nesting and social interactions. The observations were made almost daily during March to early July 1988 along the shore at a distance of 1-2 m from the fish and nests. 2) All the males in an enclosed study pool were individually marked (99 males). Furthermore, a total of 67 females were marked and observed weekly. The males were individually observed and their agonistic, courtship and parental behaviour as well as their reproductive success were quantified. Reproductive success of individual male was measured as the number of nests built, the number of successful nests, the number of hatched fry per nest. Nest sites were categorized in six types (A-F) on the basis of the proportion of vegetation cover around the nest and distance from the shore. 3) Body size and environmental factors (water temperature, water depth, changes in water level) were not correlated with reproductive success. Flooding was not a major cause of unsuccessful nesting. The brightness of nuptial colouration at the onset of breeding correlated significantly with individual success. Individual variation in the development of secondary sexual characteristics such as a nuptial colouration may have an important consequence for the lifetime reproductive success of the individuals. There was no relationship between fish density and reproductive success. 4) All males that nested more than once had begun breeding early in the season. The sooner a male started nest-building, the more opportunities he had to complete breeding cycles. 5) After an unsuccessful nest, males were significantly more likely to move their nest sites than after a successful nest. The subsequent nesting cycle was not always successful. 6) There was variation in nest-sitc location. The spatial pattern of nest distribution was strongly related to the temporal pattern, because the first males which settled, more often built their nests at sites along the shore where the nest was covered on one or two sides by vegetation. The location of nest site was significantly correlated with reproductive success. When males nested in partly concealed places along the shore, they could sometimes obtain a high reproductive success irrespective of the date of breeding initiation. Thus, reproductive success was largely determined by the timing of nest-building and nest position.

scholarly journals The influence of subcolony-scale nesting habitat on the reproductive success of Adélie penguins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annie E. Schmidt ◽  
Grant Ballard ◽  
Amélie Lescroël ◽  
Katie M. Dugger ◽  
Dennis Jongsomjit ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Colony Size ◽  
Nest Predation ◽  
Size Variation ◽  
Area Ratio ◽  
Slope Aspect ◽  
Nesting Habitat ◽  
Terrain Attributes ◽  
Small Colony ◽  
Adélie Penguins

AbstractGroup-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies was perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.

Nest-site selection in the barn swallow, Hirundo rustica: What predicts seasonal reproductive success?

2006 ◽  
Vol 84 (11) ◽  
pp. 1533-1539 ◽  
Author(s):  
Rebecca Jo Safran
Keyword(s):  
Reproductive Success ◽  
Site Selection ◽  
Nest Site ◽  
Individual Characteristics ◽  
Nest Site Selection ◽  
Hirundo Rustica ◽  
Barn Swallow ◽  
Nest Location ◽  
Nest Sites ◽  
Site Characteristics

Despite hundreds of studies, we know very little about the causes and fitness-related consequences of nest-site selection. For example, it is not typically known whether the rarely reported fitness consequences of site selection are the result of nest, individual, or nest-site variables or combinations of these factors. Reuse of previously constructed nest sites is a prevalent behavior in many animals and offers the opportunity to experimentally tease apart whether seasonal reproductive success is a function of nest, individual, or nest-site characteristics. I used observational and experimental data to test three hypotheses related to these factors in association with barn swallow ( Hirundo rustica L., 1758) nest reuse. While both nest and individual characteristics explain variation in seasonal reproductive success, nest location per se is not an important factor defining the outcome of nest-site selection. Whereas traits related to habitat and individual characteristics are likely confounded in correlational studies, my experiments demonstrate a causal relationship between seasonal reproductive success and aspects of the nest and individual, the latter explaining more variation in the model than nest characteristics. Knowledge of the relative roles of individual, nest, and nest-site attributes are important for understanding the causes and consequences of habitat selection behavior.

Marbled salamanders (Ambystoma opacum) choose low elevation nest sites when cover availability is controlled

2006 ◽  
Vol 27 (3) ◽  
pp. 359-364 ◽  
Author(s):  
David Scott ◽  
Dean Croshaw
Keyword(s):  
Reproductive Success ◽  
Reproductive Behavior ◽  
Site Selection ◽  
Nest Site ◽  
Local Environment ◽  
Breeding Site ◽  
Nest Site Selection ◽  
Growth And Survival ◽  
Nest Sites ◽  
Selective Forces

AbstractNest site selection is an important part of adult reproductive behavior because growth and survival of young are often affected by the local environment. In terrestrially nesting marbled salamanders, nest elevation is likely important to reproductive success because it is directly related to the time of hatching. We tested the hypothesis that females choose nest sites based on elevation and its correlates by controlling the availability of nesting cover, a potentially important factor in nest site selection which often covaries with elevation. Breeding adults were confined to field enclosures in which natural nesting cover had been removed and replaced with equal proportions of artificial cover in each of three elevation zones. In four enclosures that spanned from lowest to highest areas of a wetland breeding site, females used artificial nesting cover most frequently at low elevations. These results contrast with other studies in which intermediate elevations had highest nest densities, but are consistent with a conceptual model in which opposing selective forces result in locally adapted nest site selection.

Structural constraints of secondary asymmetry in male external genitalia of Noctuidae

2013 ◽  
Vol 44 (3-4) ◽  
pp. 349-372 ◽  
Author(s):  
Zoltán Varga ◽  
László Ronkay
Keyword(s):  
Reproductive Success ◽  
Complex Structure ◽  
External Genitalia ◽  
The Other ◽  
Structural Constraints ◽  
Asymmetric Structures ◽  
Other Hand ◽  
Spatial Geometry ◽  
Male External Genitalia ◽  
Working Hypotheses

The basic architecture of the external genitalia of Noctuidae (“genital capsula”) is bilaterally symmetric. Secondary asymmetry is well-known in different subfamilies and tribes. We review and interpret the functions and processes which may be responsible for secondary asymmetry (i.e., dissymmetry) of these structures in terms of structural vs. behavioural working hypotheses. We consider the genital structures as correlated elements of a complex structure (“bauplan”) in which some changes in details can be explained by selection due to optimization of the reproductive success. Major pathways of changes are, however, delimited by some structural constraints which appear in parallel in different phyletic lines of trifine Noctuidae. One of these constraints is the subsistence of symmetry in structures with own musculature. On the other hand, some rigid parts without own musculature can evolve more rapidly and divergently in connection with the different allocation of functions. Such asymmetric structures may have some selective advantages due to the more effective stimulation, on one side, and fixation of genital parts during copulation, on the other. Asymmetric structures can effectively enhance the variations of the spatial geometry but without change of the “bauplan” which can be preserved in parallel in different taxonomical groups. It means that the originally symmetric “bauplan” with its homologies can be considered as a phyletic “heritage”, while the functional dissymmetrisation driven by selective optimization is the “habitus” in which numerous homoplasies can occur.

Sign in / Sign up

Export Citation Format

Share Document