Colony cycle in the south-eastern coastal populations of Ropalidia plebeiana, the only Ropalidia wasp occurring in temperate Australia

Of the 22 species of Ropalidia occurring in Australia, only R. plebeiana is distributed in temperate areas. This wasp is abundant in the south‐eastern coastal regions of Australia, where it forms huge nest aggregations. Based on our observations in late autumn and early spring, as well as information in the literature, we outline the colony cycle of R. plebeiana in the south‐eastern coastal area of New South Wales. The nesting period lasts for approximately 9.5 months, which is unusually long for temperate polistine wasps. Most foundresses seem to return to their natal nests in early spring (mid‐August to early September) to start their own colonies by reusing pre‐existing nest combs, and the pre‐emergence stage (before the emergence of the first adult brood) lasts for approximately 3.5 months. Reproductives (gynes and males) start to emerge as adults in early March, and the reproductive‐producing period lasts until the end of May. Both the pre‐emergence stage and the reproductive‐producing period are much longer than in other temperate polistine wasps, which is discussed in terms of fluctuating temperature conditions in the area and the formation of nest aggregations, a peculiar habit for temperate populations of R. plebeiana.     

Nesting Behavior of <Emphasis Type="Italic">Gorilla gorilla diehli</Emphasis> at Kagwene Mountain,Cameroon: Implications for Assessing Group Size and Density

We recorded nesting data at 569 fresh night nest sites, comprising 7032 individual nests, of Cross River gorillas inhabiting the Kagwene Mountain in western Cameroon. The mean night nest group size was 12.4. Overall, 55% of night nests were constructed on the ground and 45% in trees. Significantly more arboreal nests were constructed in the wet season (69%), vs. the dry season (19%). Day nest construction was common at Kagwene (n = 260 nest sites, mean nest group size = 5.98) and we encountered significantly more day nest sites in the wet season. Nest site reuse was also common (35%), though not related to season. Our results of nesting habits concur with those from other western gorilla studies, in which rainfall influences arboreal nesting. However, we encountered wet season arboreal nesting, day nest construction, and overall nest site reuse more frequently than reported for other sites. Our observations have considerable implications when estimating group size and density using traditional nest count data. The gorillas at Kagwene inhabit the highest altitudinal range of all Cross River gorilla subpopulations and rainfall is also high; therefore other subpopulations may demonstrate different nesting characteristics. However, one should consider our findings when attempting to estimate Cross River gorilla density at other localities through nest site data.     

Effect of floating nest platforms on the breeding performance of Black Terns

ABSTRACT.   In 2003 and 2004, we placed 41 floating nest platforms on Grassy Lake in southeastern Wisconsin (USA) to test the hypothesis that reproductive success of Black Terns ( Chlidonias niger ) is limited by the quality of suitable nesting habitat. Extreme differences in water levels between these 2 yr provided a natural experiment to evaluate the effectiveness of the nest platforms during a drought year (2003) when natural nesting substrate was abundant, and a flood year (2004) when natural substrate was limited during the peak nesting period. Terns nested on 27 of 41 (66%) of the platforms in 2003 and 26 of 41 (63%) in 2004. No difference in the occupancy rate of platforms and natural nests was evident in 2003, but the pattern of clutch initiations early in the season in 2004 indicated that platforms were preferred over natural substrates. In 2003, nest survival rates did not differ between nests placed on platforms and those placed on natural substrates, but platform nests had significantly higher hatching success and nest survival rates in 2004. Both the Kaplan-Meier and Apparent Nest Success methods of calculating nest survival provided similar estimates. In both years, eggs laid on platforms were significantly larger than those laid on natural substrates, suggesting that platforms were occupied by high-quality birds. Our study indicates that floating nest platforms can be an effective management tool to enhance nesting habitat for Black Terns and other aquatic birds that construct floating nests, primarily because platforms provide nest sites when natural sites are not available due to flooding. Nest platforms also may be useful for addressing questions concerning habitat selection and parental quality.     

Selection and sharing of sheltered nest sites by ants (Hymenoptera: Formicidae) in grasslands of the Australian Capital Territory

Abstract  In this study, it was investigated whether ants nesting under artificial rocks in a mesic south-eastern Australian grassland showed preference for nest sites with different temperature regimes. The study also allowed evaluation of competition between species for nest sites and observations of seasonality in brood and alate production in the nests of four common ant groups. On every sampling occasion more than 90% of nests were either Iridomyrmex spp., Rhytidoponera 'metallica' , Paratrechina sp. or Pheidole spp. Soil underneath thinner artificial rocks had higher average temperatures and warmed up earlier in the day and Iridomyrmex spp. and R. 'metallica' showed preference for establishing nests under these. While all ant nests had summer peaks in brood production, Iridomyrmex spp. and R. 'metallica' had brood observed throughout the year. Winged reproductives were commonly encountered in Iridomyrmex spp., R. 'metallica' and Paratrechina sp. nests, but only occasionally Pheidole spp. nests. Alates were present in the nests from February but released by all taxa after spring rains and were scarcely recorded in November, December and January when brood production was observed in most nests. Nest sites that offer protection from predators are an obvious advantage, but improved reproductive success can be gained in cool regions such as the mesic grasslands of the Australian Capital Territory by choosing nest sites with an optimal thermal regime.     

Colony Foundation and Nestmate Recognition in the Social Wasp,Belonogaster petiolata

Emergence from hibernation and synchronized nest foundation by foundresses of B. petiolata in the southern Transvaal, appeared to be stimulated largely by a rise in temperature during early and mid August of each season. Initial foundresses on newly built nests were joined by other foundresses during the first few weeks of the nesting season to form foundress associations. Although females were strongly philopatric and able to discriminate between nestmates (from their natal nests) and non-nestmates, former nestmates did not reassociate to a significant degree on new nests. Thus, associated foundresses were, on average, not closely related. Rather than facilitating the reassociation of former nestmates, the advantage of philopatric behaviour appears to lie in ensuring that foundresses return to an area of relatively high nesting density, where their chances of being involved in multiple-foundress groups (irrespective of intra-colonial relatedness) are high. Non-philopatric females which nest away from localities of high nesting density have a low probability of being involved in associations, and may therefore have to attempt colony foundation alone, with little or no chance of reproducing successfully.     

An inexpensive method for remotely monitoring nest activity

ABSTRACT.   In studies of avian nest success, investigators often face the difficult task of periodically checking nest status while at the same time limiting observer influence on nest survival. Remotely monitoring nests using temperature data loggers is one method that allows for continuous data capture regarding nest status (i.e., active vs. inactive) without the negative effects associated with repeated nest checks. We used small temperature data loggers (Thermochron iButtons) to remotely monitor nests of Long-billed Curlews ( Numenius americanus ) in northeastern Nevada. Data loggers programmed to record temperature at 10-min and 20-min intervals were placed in curlew nests. Data loggers were set to collect data throughout the nesting cycle to determine onset of incubation and timing of nest failure. On average, Long-billed Curlews began incubating approximately 3 d after the first egg was laid and onset of incubation coincided with the laying of the third egg. iButtons allowed us to determine when incubation was terminated in 17 of 23 unsuccessful Long-billed Curlew nests, including 13 of 17 depredated nests. The presence of iButtons in Long-billed Curlew nests did not affect daily survival rate, egg hatchability or rate of nest abandonment. iButtons are an efficient and practical means for remotely monitoring nests of large egg-laying birds, such as the Long-billed Curlew.     

Determinants of reproductive success and offspring sex in a turtle with environmental sex determination

Despite the importance of maternal effects in evolution, and knowledge of links among nest site choice, timing of nesting, offspring sex, and reproductive success in animals with environmental sex determination, these attributes have not been rigorously studied in a combined and natural context. To address this need we studied the relationships between three maternal traits (nest site choice, lay date, and nest depth) and two fitness‐related attributes of offspring (hatchling sex and embryonic survival) in the riverine turtle Carettochelys insculpta, a species with temperature‐dependent sex determination, for four years. Predation and flooding were the major sources of embryonic mortality in 191 nests. Embryonic survival was influenced by both lay date and nest site choice: in one year when nesting began later than average, nests laid later and at lower elevations were destroyed by early wet season river rises. In other years early nesting precluded flood mortality. However, turtles did not nest at the highest available elevations, and a field experiment confirmed that turtles were constrained to nest at lower elevations where they could construct a nest chamber. The principal determinant of hatchling sex in 140 nests was lay date, which in turn was apparently related to the magnitude of the previous wet season(s). Clutches laid earlier in the season (a female's first clutch) produced mainly males, while later clutches (her second clutch) yielded mostly females, due to seasonal increases in air temperatures. Accordingly, later nesting produced female‐biased hatchling sex ratios in 1996, while earlier nesting resulted in sex ratios near unity in the other years. However, all‐female nests were more likely to be flooded than mixed‐sex or all‐male nests in years when nesting was late. In conclusion, we found evidence that the position of two maternal trait distributions (elevation of the nest site and lay date), associated with the reproductive strategy of C. insculpta, reflect a combination of natural selection, physical constraints, and phenotypic plasticity. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81 , 1–16.     

Can nest predation and predator type explain variation in dispersal of adult birds during the breeding season ?

Many types of predators depredate bird nests and thus potentiallyinfluence the spatial distribution of their prey. We used asimulation model of a double-brooded songbird's nesting seasonto test three predictions about the selective advantage ofdispersing different distances after nest predation by predatorswith varying home range sizes. Our results supported the predictions that (1) dispersing birds had higher success than nondispersingbirds after predation of the first nest, (2) dispersing beyondthe home range of the nest predator increased the success ofthe second nest, and (3) birds whose first nests were depredatedearly in the nesting cycle did better by dispersing fartherthan birds whose nests were depredated later in the nestingcycle. Our results provide evidence that predation and predatorcharacteristics may cause variation in adult dispersal distancesduring the breeding season. However, we did not find an advantagefor long-distance dispersal when predators with small- or medium-sizedhome ranges were responsible for the predation event. The criticaldecisions of dispersal and dispersal distance made by adultbirds are complex, but our model demonstrates that predationevents can create a selective advantage to disperse.     

Issue Information

The population of Yellow‐naped Amazons (Amazona auropalliata) declined by an estimated 50% between 1980 and 2000, and the current population is estimated to be between 10,000 and 50,000. Poaching of young has been a persistent problem, but the species is also threatened by habitat loss and degradation. Because most aspects of their life history, behavior, and ecology have not been examined in wild populations, we studied Yellow‐naped Amazons with the following objectives: (1) identify the species of trees used for nesting, (2) determine the size and potential function of breeding territories, (3) determine nesting success, and (4) examine their duetting behavior. We located nests at 16 sites on the Pacific Slope of Costa Rica from 1999 to 2008. We searched for nests from January to May. Every nest was visited at least once and some nests were visited every 2–3 weeks throughout the breeding season. We also collected territory and duetting data at one site (Ahogados). The breeding season of Yellow‐naped Amazons was during the dry season (January–May). Yellow‐naped Amazons nested in 21 species of trees, but 68% of nests were located in only five species, and cavities in dead coyols (Acrocomia aculeata) were used most often. We found no association between breeding success and the species of tree in which birds nested. Mean territory size was 25,578 m², and these small areas generally consisted of several trees surrounding a nest tree. Pairs continued to duet throughout the breeding season, suggesting that duetting is important for territory defense. The nest failure rate in our study was 89%, and most nest failures (64%) were due to poaching for the pet trade. We recommend immediate population management and conservation actions, including increased law enforcement to reduce nest poaching, protection of key nesting areas, educational programs, and habitat conservation.     

Nesting biology and nest re-use ofEulaema nigrita (Hymenoptera: Apidae,Euglossini)

Summary The nesting behavior of the euglossine beeEulaema nigrita was observed in the laboratory after being transferred from three nests to observation boxes. Nests were re-used by successive generations with more than one female working in each re-use process. Associated females were always of the same generation. All females that shared a nest foraged for construction materials (mud, excrement and resin) and each constructed, provisioned and oviposited in her own cells. The number of cells constructed by each female ranged from one to 23. Females stayed in the nests for periods ranging from 15 to 59 days during the hot and wet season and from five to 78 days during the cool and dry season. The egg-to-adult period was related to climatic conditions, and in all re-use processes it was longer than the time of residence of the females in the nests. The meloid beetleMeloetyphlus attacephalus was the only nest parasite. Due to the attack method employed by this parasite, the presence of more than one female in the nest did not result in improved nest defense.