Nesting Behavior Research Articles

Spatial and temporal variation in nest temperatures forecasts sex ratio skews in a crocodilian with environmental sex determination.

Species displaying temperature-dependent sex determination (TSD) are especially vulnerable to the effects of a rapidly changing global climate due to their profound sensitivity to thermal cues during development. Predicting the consequences of climate change for these species, including skewed offspring sex ratios, depends on understanding how climatic factors interface with features of maternal nesting behaviour to shape the developmental environment. Here, we measure thermal profiles in 86 nests at two geographically distinct sites in the northern and southern regions of the American alligator's (Alligator mississippiensis) geographical range, and examine the influence of both climatic factors and maternally driven nest characteristics on nest temperature variation. Changes in daily maximum air temperatures drive annual trends in nest temperatures, while variation in individual nest temperatures is also related to local habitat factors and microclimate characteristics. Without any compensatory nesting behaviours, nest temperatures are projected to increase by 1.6-3.7°C by the year 2100, and these changes are predicted to have dramatic consequences for offspring sex ratios. Exact sex ratio outcomes vary widely depending on site and emission scenario as a function of the unique temperature-by-sex reaction norm exhibited by all crocodilians. By revealing the ecological drivers of nest temperature variation in the American alligator, this study provides important insights into the potential consequences of climate change for crocodilian species, many of which are already threatened by extinction.

Communal egg‐laying behaviour and the consequences of egg aggregation in the brown anole (Anolis sagrei)

AbstractCommunal nesting is a behaviour that involves multiple females laying eggs in the same nest or nesting site. This behaviour may be a consequence of a shortage of preferable nest sites (constraint hypothesis) or an adaptation generated by fitness benefits associated with egg aggregation (adaptive hypothesis). Experimental tests of these hypotheses require information about maternal nest site choice and its fitness consequences. To address these, we studied a lizard (brown anole; Anolis sagrei) that produces single‐egg clutches, but often aggregates eggs in nest sites. In a lab study, females were given the option of nesting in (a) soil previously used as nest substrate vs. fresh soil and (b) soil with eggshells vs. without eggshells. We also experimentally examined the effects of egg aggregation by incubating eggs singly, in groups of four, and in groups of nine. We recorded egg surface temperature, water uptake, and hatchling morphology. Females were more likely to nest in pots with used soil and with eggshells than in pots with fresh soil or without eggshells. We observed no effects of egg aggregation on egg survival, egg temperature, or most measures of hatchling morphology. However, singly‐incubated eggs absorbed more water than eggs incubated in the four and nine egg aggregations and this resulted in offspring with greater body condition (i.e. heavier for their length) at hatching. The behavioural experiment demonstrates that females actively choose nest sites that have been used previously (as expected under the adaptive hypothesis), but the egg‐aggregation experiment shows no benefits to offspring based on the variables measured. Thus, results of the behaviour study support the adaptive hypothesis; however, results from our egg‐incubation study do not. Likely, the adaptive and constraint hypotheses are not mutually exclusive, and a diversity of factors influence the evolution of communal nesting behaviour.

Geolocators lead to better measures of timing and renesting in black‐tailed godwits and reveal the bias of traditional observational methods

Long‐term population studies can identify changes in population dynamics over time. However, to realize meaningful conclusions, these studies rely on accurate measurements of individual traits and population characteristics. Here, we evaluate the accuracy of the observational methods used to measure reproductive traits in individually marked black‐tailed godwits (Limosa limosa limosa). By comparing estimates from traditional methods with data obtained from light‐level geolocators, we provide an accurate estimate of the likelihood of renesting in godwits and the repeatability of the lay dates of first clutches. From 2012 to 2018, we used periods of shading recorded on the light‐level geolocators carried by 68 individual godwits to document their nesting behaviour. We then compared these estimates to those simultaneously obtained by our long‐term observational study. We found that among recaptured geolocator‐carrying godwits, all birds renested after a failed first clutch, regardless of the date of nest loss or the number of days already spent incubating. We also found that 43% of these godwits laid a second replacement clutch after a failed first replacement, and that 21% of these godwits renested after a hatched first clutch. However, the observational study correctly identified only 3% of the replacement clutches produced by geolocator‐carrying individuals and designated as first clutches a number of nests that were actually replacement clutches. Additionally, on the basis of the observational study, the repeatability of lay date was 0.24 (95% CI 0.17–0.31), whereas it was 0.54 (95% CI 0.28–0.75) using geolocator‐carrying individuals. We use examples from our own and other godwit studies to illustrate how the biases in our observational study discovered here may have affected the outcome of demographic estimates, individual‐level comparisons, and the design, implementation and evaluation of conservation practices. These examples emphasize the importance of improving and validating field methodologies and show how the addition of new tools can be transformational.

Sound production of the banded Sculpin, Cottus carolinae

The use of sound in social interactions has been documented in several species of sculpin and may be used to convey information concerning species identity, intent, or fitness. Sound production may be a particularly important mode of communication in sculpin due to their nocturnal behavior and construction of nests in rock cavities where the efficacy of visual cues may be diminished. In this study, we describe acoustic signals produced during conspecific behavioral interactions in Cottus carolinae, and compare signal characteristics to the only other known sounds producers in the genus Cottus including C. gobio, C. rhenanus, C. perifretum, C. bairdii, and C. paulus. Sounds were produced during nocturnal encounters between cavity residents and intruders, and consisted of pulsatile signals that were arranged into pulse trains with remarkably long pulse intervals of approximately 1 s, as well as tonal sounds in which the periodicity was increased to approximately 60 Hz. We found no relationship between fish standard length and pulse instantaneous frequency or total pulse train duration, but did find a positive correlation between fish standard length and pulse duration, as well as position of pulse interval within the pulse train. We found that C. carolinae pulse train structure differed significantly from that of other published sculpin species, and that C. carolinae produce tonal sounds; a characteristic unique within the genus Cottus.

Intriguing electronic and optical prospects of FCC bimetallic two-dimensional heterostructures: epsilon near-zero behavior in UV-Vis range.

A higher superconducting critical temperature and large-area epsilon-near-zero systems are two long-standing goals of the scientific community, having an explicit relationship with the correlated electrons in localized orbitals. Motivated by the recent experimental findings of the strongly correlated phenomena in nanostructures of simple Drude metallic systems, we have theoretically investigated some potential bimetallic FCC combinations having close resemblance with the experimental systems. The explored systems include the large-area interface to the embedded and doped two-dimensional (2D) combinatorial nanostructures. Using different effective single-particle first-principles approaches encompassing density functional theory (DFT), time-dependent DFT (TDDFT), phonon and DFT-coupled quantum transport, we propose some interesting correlated prospects of potential bimetallic nanostructures like Au/Ag and Pt/Pd. For the 2D doped and embedded nanostructures of these systems, the DFT-calculated non-trivial band-structures indicate the interfacial morphology-induced band localization. The calculated Fermi-surface topology of the nanostructures and the corresponding nesting behavior may be emblematic to the presence of instabilities, such as charge density waves. The optical attributes extracted from the TDDFT calculations result in near-zero behavior of both real and imaginary parts of the dynamical dielectric response in the ultra-violet to visible (UV-Vis) optical range. In addition, low-energy intra-band plasmonic oscillations, as present for individual metallic surfaces, are completely suppressed for the embedded and doped nanostructures. The TDDFT-derived electron-energy loss spectra manifest the survival of only inter-band transitions. The presence of soft phonons and dynamic instabilities is observed from the phonon-dispersion of the nanostructured systems. Quantum transport calculations on the simplest possible device made out of these bimetallic systems reveal the generation of highly transmitting pockets over the cross-sectional area for some selected device geometry. We envisage that, if scrutinized experimentally, such systems may unveil many fascinating interdisciplinary aspects of orbital chemistry, physics and optics, promoting their relevant applications in many diverse fields.

Nestled in the city heat: urban nesting behavior enhances embryo development of an invasive lizard

Abstract Urbanization transforms many aspects of natural landscapes and poses many new challenges for individual survival and population persistence. Thus, urbanization provides an opportunity to examine how organisms deal with novel environmental change. Many studies provide evidence of phenotypic adaptation to urban environments, but few focus on responses during early life stages. Filling this information gap is important, because early life stages are particularly sensitive to abiotic factors, and no population is sustainable without successful embryo development. We tested the hypotheses that (i) embryos tolerate warmer temperature conditions of urbanized areas and (ii) maternal nesting behavior protects embryos from potentially lethal thermal conditions in urbanized habitats. We studied introduced populations of a subtropical lizard, Anolis cristatellus, in suburban and forested areas in Miami, Florida. In each habitat, we measured microenvironment variables for locations that females used for nesting vs. locations they did not use. We then incubated eggs from both populations under thermal conditions that mimicked used and unused sites. Nests in the suburban site were warmer than in the forest; however, in the suburban site, locations that females used were relatively cool compared with locations that were not used. We found no evidence that embryos are adapted to their respective suburban or forested thermal environments, but rather maternal nest-site choice enhanced embryo development in the suburban habitat. Maternal nesting behavior is likely an important factor for population persistence under major environmental changes, and a key contributor to the establishment and spread of invasive organisms across urbanized landscapes.

Dibutyl phthalate exposure during gestation and lactation in C57BL/6 mice: Maternal behavior and neurodevelopment in pups

ObjectivesNeurotoxic effects of phthalate during pregnancy on immature brain of the offspring or mature brains of the mothers remain unclear. We examined the effect of dibutyl phthalate (DBP) exposure during gestation and lactation on the maternal behavior of mother mice and neurodevelopment in pups. MethodsPregnant mice were treated orally with DBP (0, 50 and 100 mg/kg/day, N = 20 per group) from gestational day 13 to postnatal day (PND) 15. Maternal behavior was measured using pup retrieval and nest shape test at postpartum day 4. For the pups, the neurodevelopment was measured using negative geotaxis, cliff avoidance at PND 7, swimming test and olfactory orientation at PND 14. RNA and protein expressions in the brain cortex of 50 mg/kg/day and control group (0 mg/kg/day) were analyzed using microarray and Western blot analysis. Nissl-stained sections at the coronal level of interaural 2.56 mm, bregma −1,23 mm, were used for counting of dark cortical neurons in mother and pup mice. ResultsDBP treated mother mice (50 and 100 mg/kg/day) showed poor maternal behavior, poor nesting and retrieval behavior compared to the control group (0 mg/kg/day). In brain cortex, DBP-treated mothers showed decrease in protein expression of Nr4a3, Egr1, Arc, BDNF and phosphorylation of AKT and CREB, were also decreased in cortex of DBP-treated mothers. Pups exposed to DBP showed significantly decreased scores in negative geotaxis at PND 7 and swimming scores and olfactory orientation tests at PND 14. The cortex of the DBP exposed pups showed increase in expression of dopamine receptor D2 gene. Nissl staining showed that the dark neurons were increased in cortex of DBP treated mothers and DBP exposed pups. Suggesting that phthalate may delay pup development indirectly through inadequate mothering as well as direct phthalate exposure on the brain. ConclusionDBP exposure during gestation and lactation cause impairment in maternal behaviors and downregulation of neuronal plasticity and survival signals. Pups of mothers with exposed to DBP, showed delayed neurodevelopment and dark neurons increase in brain cortex, suggesting that phthalate may delay pup development indirectly through inadequate mothering as well as direct phthalate exposure on the brain.

Prenatal light exposure influences gait performance and body composition in bobwhite quail chicks

Maternal nesting behavior, which includes periods of patterned inattention, provides key elements essential for avian embryonic development, including regulation of temperature and light. For example, avian research consistently shows the importance of prenatal light exposure for several developmental processes; however, this research has primarily focused on artificial light regimens (i.e. 24 hr, 0 hr light). Comparatively less is known about how exposure to naturally occurring light patterns during incubation influence motor performance, body composition (i.e. body mass, bone length), and developmental age (incubation length). Here we conducted two experiments which investigated the effects of prenatal light exposure on developmental age, body composition, and gait performance in 1-day-old bobwhite quail. Experiment 1 investigated crepuscular light exposure during the last two days of incubation under two light duration treatments (2 hr & 6 hr) compared to a 12 hr continuous light schedule. Results indicated crepuscular prenatal light experience extended the incubation period for 2 hr exposed embryos, but not for 6 hr exposed embryos and negatively influenced postnatal body composition and postnatal gait performance when compared to 12 hr continuous light embryos. Experiment 2 examined the influence of prenatal light duration (2 hr vs 6 hr) and light presentation (crepuscular vs sporadic). Results demonstrated sporadic light presentation improved gait performance in 2 hr exposed hatchlings, but not 6 hr exposed hatchlings, improved body composition in 6 hr exposed hatchlings, but not 2 hr exposed hatchlings, and did not alter incubation length when compared to crepuscular light counterparts. This study provides further evidence for the importance of maternally regulated sensory stimulation during the prenatal period on early postnatal motor development.

Nest Building Behavior as an Early Indicator of Behavioral Deficits in Mice.

Nest building is an innate behavior in male and female rodents, even when raised in laboratory settings. As such, many researchers provide rodents synthetic and/or natural materials (such as twine, tissue, cotton, paper, and hay) as a gauge of their overall well-being and as an ancillary assessment to predict the possible decline in cognition. Typically, changes in nesting behaviors, such as failure to create a nest, indicate a change in health or welfare. In addition, nesting behavior is sensitive to many environmental and physiological challenges, as well as many genetic mutations underlying pathological disease states. The following protocol describes a nesting behavior paradigm that explores the usage of four types of nesting material. In addition, the protocol utilizes intraclass correlations to demonstrate that inter-rater reliability is higher when nests are constructed out of shredded paper compared to other common nesting materials such as cotton squares, paper twists, and soft cob bedding. The chosen methodology and statistical considerations (i.e., intraclass correlation) for this assay may be of interest for those conducting experiments assessing the quality of living of mice.

Nest Building Behavior as an Early Indicator of Behavioral Deficits in Mice

Nest building is an innate behavior in male and female rodents, even when raised in laboratory settings. As such, many researchers provide rodents synthetic and/or natural materials (such as twine, tissue, cotton, paper, and hay) as a gauge of their overall well-being and as an ancillary assessment to predict the possible decline in cognition. Typically, changes in nesting behaviors, such as failure to create a nest, indicate a change in health or welfare. In addition, nesting behavior is sensitive to many environmental and physiological challenges, as well as many genetic mutations underlying pathological disease states. The following protocol describes a nesting behavior paradigm that explores the usage of four types of nesting material. In addition, the protocol utilizes intraclass correlations to demonstrate that inter-rater reliability is higher when nests are constructed out of shredded paper compared to other common nesting materials such as cotton squares, paper twists, and soft cob bedding. The chosen methodology and statistical considerations (i.e., intraclass correlation) for this assay may be of interest for those conducting experiments assessing the quality of living of mice.

Relative preference for wooden nests affects nesting behaviour of broiler breeders

Optimising nest design for broiler breeders has benefits for both the animals and the producers. The welfare of the hens will increase by providing preferred housing, while also reducing eggs laid outside the nests. These floor eggs cause economic losses by compromised automatic egg collection and reduced saleability and hatchability. Attractiveness of nests can involve factors such as seclusion, material and microclimate. In this study, four nest box designs were offered in a relative preference test: a plastic control nest, a plastic nest with a partition to divide the nest in two areas, a plastic nest with a ventilator underneath to create air flow inside the nest and a wooden nest. Six groups of 100 hens and 9 roosters had access to these four nests in a randomised location during the ages of 20 to 34 weeks. Nest and floor eggs were collected five days a week. Camera images from inside the nests made during the ages of 24–25 weeks and 26–27 weeks were analysed for behaviour. This included general activity, nest inspections, nest visits and social interactions. At 32 weeks of age the wooden nests were closed, and the subsequent response of the hens was monitored in terms of number of eggs. We found a clear preference in number of eggs for the wooden nest (69.3 ± 1.0%) compared to the control nest (15.1 ± 0.8%), partition nest (10.2 ± 0.5%) and the ventilator nest (5.4 ± 0.4%; p<0.0001 for difference between all nest designs). The preference for the wooden nest was also reflected in an increased time spent sitting, together with fewer nest inspections and visits per egg laid in the wooden nest. The preference for the wooden nest led to crowding, which caused an increased amount of piling, nest displacement, aggression and head shaking. The fact that the hens were willing to accept the crowded circumstances in these nests, underlines the strength of this preference. After the wooden nests were closed, the hens chose a new nest based on a combination of nest design and location. The control nest was still preferred over the other two plastic designs, although the neighbouring nests were overall preferred to the non-neighbouring nests. This study shows how the material used for nests is an important factor in suitability and should therefore be taken into account when designing nests.

Effects of sun exposure and vegetation cover on Woodpecker nest orientation in subtropical forests of South America

Variations in the orientation behavior of Woodpecker nests can be due to environmental factors such as latitude as well as local climate conditions. In this study, the orientations of dot-fronted Woodpecker nesting cavities (Veniliornis frontalis, Picidae) were examined at a subtropical site in Northwestern Argentina. It was evaluated whether solar radiation influences the mean orientation of cavities well covered by vegetation and cavities with less or non-external vegetal protection. Results obtained in this work provide that both covered and uncovered nests orient in a defined way towards the North and the Northwest, respectively, finding mean differences between both types of vegetation cover. These results indicate that, being exposed to the North (protected cavities) they get more solar radiation during the day to reduce the humidity of cavities’ microhabitat, due to the intense rainfall; and Northwest (unprotected cavities); to increase the temperature within the cavity due to the low night temperatures and humid climate. This study highlights the importance of studying the vegetation over the nests (protection) together with the local climatic conditions, given that they are important determinants for bird nest orientation.

Occurrence and nesting behavior of social wasps in an anthropized environment

Some effort had been made concerning the social biodiversity of wasps in Brazil; however, few approaches have been made relating to how this taxa have adapted their nesting behavior to anthropic mixed environments. Thus, the present work aimed to survey the occurrence of social wasps in an anthropic area and their relationship with different types of nesting substrates. Increasing the knowledge of social wasps in anthropic areas would allow us to develop strategies for their conservation and management. Twenty long-term surveys were made at the Universidade de São Paulo, Ribeirão Preto campus, São Paulo State. During the searches, we collected information about wasp species and nesting substrate. A total of 20 species of 8 genera were identified, and a total of 431 active colonies were registered. Epiponini was the richest in terms of species richness. On the other hand, Mischocyttarini was represented by more active colonies. Mischocyttarus cerberus had a remarkably greater number of colonies, which agreed with the idea of preference of anthropic environments by independent founding wasps. Nesting behavior was associated with eight substrate categories. We observed that some species might express certain plasticity regarding their nesting substrate usage, whereas some expressed certain specificity. Facing the increase in the actual urbanization process and, consequently, habitat loss, this type of study might contribute towards better understanding how these insects are affected by altered environment.

Analysis Of Behavior The Eradication Of Family Mosquito Nest With Larva Mosquito Free Number

Many people are still not aware of the cleanliness of the environment and the slow pace of the government in anticipating and responding to the spread of dengue cases. The aim of the study was to have a relationship between the behavior of eradicating mosquito nests and larvae in Paleleh Village, Paleleh District, Buol District, Central Sulawesi Province.&#x0D; The design used in the study was cross sectional. Population is all families. The sample size was 168 respondents using Purposive Sampling techniques. Independent variable research is behavior. The dependent variable is the larva mosquito free number. Data was collected using a questionnaire, then the data were analyzed using the Spearman Rho test, with a significance level of α ≤ 0.05.&#x0D; The results showed that most respondents had sufficient mosquito nest eradication behavior as many as 106 respondents (63.1%), free larvae as many as 138 respondents (82.1%), statistical test results obtained p = 0,000 with a = 0.05, there is a significant relationship in the variable of eradicating mosquito nest behavior in the presence of larvae, with a correlation coefficient of 0.773 which means having a strong relationship.&#x0D; Flicking eradication behavior has an impact on the existence of larvae in the family so that sufficient behavior needs to be continuously improved in order to be good.

Host-parasitoid interactions between the solitary bee Centris analis (Apidae: Centridini) and conopid flies (Diptera: Conopidae).

Natural enemies are one of the main mortality factors in bees and wasps attacking either immature stages or adults of their hosts. Dipterans of the genus Physocephala (Diptera: Conopidae) are parasitoids that attack adult bees during their field activities, and the parasitoid larvae develop inside the host abdomen. However, little is known about the biology of these natural enemies and their interactions with their solitary bee hosts. This study is aimed at analyzing attacks by conopid flies in one of their hosts, the solitary bee species Centris analis (Apidae: Centridini), and the consequences in the nesting behavior of this bee species. Higher incidences of parasitism occurred during the hot/wet season, and seven fly species attacking C. analis were identified. Of the fifty-six females observed during their nesting activities, seven of them were parasitized. These females showed alterations in their nesting behavior, depositing extra oil on the plug of finished nests and building plugs in empty cavities. The behavioral changes observed in these females began during larval stage L1 of the parasitoid. In the last stages of parasitoid development (L3 PUP and pupa), the bees ceased their flight activities and entered cavities at the nesting site, remaining there until death.

First account of the breeding biology of Brown Parrotbill (Cholornis unicolor, Aves: Sylviidae) in Gaoligongshan National Nature Reserve, Yunnan, China

The Brown Parrotbill (Cholornis unicolor) is endemic to the central and eastern Himalayas and occurs in alpine bamboo thickets at an altitude of 1,980–3,600 m. Fieldwork was conducted in the Gaoligongshan National Nature Reserve and cameras were used to record reproductive behaviors. Duration of incubation, nestling provisioning, and other parental care behaviors were extracted from the videos, and measurements of the nest, eggs, and nestlings were taken in the field. One nest with a clutch of 3 eggs was found 2.1 m above the ground in a bamboo thicket in May, thus extending the documented breeding season. Two of the three eggs hatched and both nestlings fledged. Both the male and the female incubated the eggs and brooded and provisioned the nestlings. The incubation period lasted for at least 13 d and the nestling period was 15 d. As incubation progressed, incubation-bout duration decreased and recess frequency increased. During the nestling period, the frequency of parental provisioning increased as the nestlings matured. Our observations provide the first description of the nest, nestlings, and incubation behavior of Brown Parrotbill. Alpine bamboo thickets are assumed to be an important breeding habitat for Brown Parrotbills, as this is typical for at least 6 parrotbill species.

First Report of Female Giant South American River Turtles (Podocnemis expansa) Being Buried Alive During Nesting

Abstract Podocnemis expansa is the only freshwater turtle species that presents a social nesting behavior in South America, where thousands of females congregate on nesting beaches. We recorded the...

The influence of maternal nesting behaviour on offspring survival: evidence from correlational and cross-fostering studies

The maternal effect of nesting behaviour is important in oviparous species because choice of microhabitat (e.g. shade cover, temperature) can determine the environment in which embryos develop. In turn, this maternal choice can influence developmental trajectories and offspring phenotypes and survival. We studied maternal nesting behaviour in a western painted turtle, Chrysemys picta, population in northern Idaho, U.S.A. During 2013–2016, we examined maternal choice of nest microhabitat and used correlational data to quantify consequences on egg survival. In 2017, we conducted a cross-fostering experiment to decouple the effects of intrinsic maternal effects from extrinsic environmental factors on egg survival, while simultaneously manipulating the level of nest shade cover and distance from water using artificial nests. Females chose nest sites that were more open and warmer than randomly available habitat. Additionally, of three nesting areas, the coolest area with the most shade cover was used least by nesting females. Egg survival was associated with nest temperature in some, but not all, years. In the cross-fostering experiment, egg survival did not differ between natal and foster eggs, but was greater in maternal nests than in artificial nests. Additionally, egg survival increased with canopy openness and minimum nest temperature, especially for eggs in artificial nests. Overall, these results suggest that females select nesting conditions (warm and open nest sites) that positively affect hatching success.

Do Local Environmental Factors and Lunar Cycle Influence Timing and Synchrony of Oviposition of a Turtle with Strict Nocturnal Nesting?

Timing of nesting affects fitness of oviparous animals living in seasonal environments, and females may cue on environmental factors for their nesting behavior, but these relationships are understudied in tropical turtles. Here, the timing and synchrony of egg-laying relative to environmental factors were examined in the South American freshwater turtle Podocnemis unifilis on 11 nesting beaches during three nesting seasons. Daily measurements included number of nests laid, rainfall, river level, air temperature, and the phase of the lunar cycle (full moon, last quarter, new moon and first quarter). Results confirmed that P. unifilis nested at night and revealed that females in our population nest in groups from 2 to 17 females at a time. Nesting was not correlated with rainfall, but a significant relationship was found with river level, such that nesting started at the onset of the dry season when river levels dropped and nesting grounds emerged. Importantly, we found that (1) nesting events concentrated on days with intermediate daily maximum air temperature (although maxima changed annually), and that (2) larger groups of females nested around full moon, suggesting the reliance on visual cues to initiate nesting activities (consistent with social facilitation behavior). Altogether, the timing of nesting in P. unifilis may be shaped by a combination of environmental factors, moon phase and social facilitation, where visual cues play an important role.

NOTES ON NESTING AND GREGARIOUS BEHAVIOR OF A BLUE NEST-RENTING WASP, CHALYBION JAPONICUM (GRIBODO) WITH COMMENTS ON COMMONLY USED NAME FOR CHALYBION SPECIES (HYMENOPTERA: SPHECIDAE)

Notes on nesting and gregarious behavior of the blue nest renting wasp Chalybion japonicum (Gribodo) are presented. Three focal nests, freshly attached to the walls of an abandoned house belonging to the mud dauber wasp Sceliphron madraspatanum were occupied by C. japonicum, suggesting that the wasp is a nest invader of S. madraspatanum. Aggregation of C. japonicum males on the string of the sack, which hung loosely beneath the ceiling, undoubtedly plays a role to help males finding females easily rather than by having to take flight. Discussion on relationship of occurrence between C. japonicum and C. bengalense is included. The new appellation “nest renting wasps” for Chalybion species is suggested.