German Yellowjacket (Vespula germanica) Foragers Use Odors Inside the Nest to Find Carbohydrate Food Sources

Prior work has shown that yellowjacket waSPS remember food odors and use them as cues when foraging. There is also evidence they have mechanisms to recruit nest mates to highly rewarding food sources, as naïve individuals are more likely to go to food sources with scents similar to those visited by nest mates. We asked whether recruitment requires behavioral stimulation by returning foragers, as in honey bees, or if sampling the food source inside the nest is sufficient. We tested this by eliminating the behavior of returning foragers by inserting a scented sugar solution directly into a Vespula germanica nest. Exiting foragers were given a choice of the test scent and a control scent. WaSPS were more likely to choose the test scent. We conclude that behavioral interactions with returning foragers are not necessary to stimulate nest mates to associate an odor with a food source and search for a resource bearing that odor, and that experience with the scented reward inside the nest is sufficient to achieve this result.     

Sound production and chorusing behaviour in larvae of Icosium tomentosum

Substrate-borne vibrations produced by the larvae of non-lamiinae longicorn Icosium tomentosum Lucas, 1854 (Cerambycidae: Cerambycinae) are also emitted as loud sounds audible to humans. The vibrations consists of a long sequence of regularly repeated pulses at a rate of 8 pulses per second. The duration of the pulses are 0.061±0.009 s and the interpulse intervals are 0.065±0.015 s. The mechanism of vibration generation is the scraping by strongly sclerotised mandibles against the bark. Chorusing behaviour previously unknown in Cerambycidae larvae have been observed when the larvae feeding in the same or nearby branches starting to produce the audible vibrations in reaction to the vibrations of another larva.     

Snake behavior and seasonal variation in nest survival of northern cardinals Cardinalis cardinalis

Seasonal variation in nest success is well documented for many bird species. Predator behavior has been suggested as a mechanism behind these seasonal patterns, but this hypothesis has received little attention. Here we test the hypothesis that predator behavior produces seasonal patterns of nest success by relating nest success of northern cardinals Cardinalis cardinalis to the activity of Texas rat snakes Elaphe obsoleta. Cardinal nest survival varied over the season and was lower when rat snakes were more active. The probability that a nest survived was associated both with when cardinals nested and with nest height, indicating that both temporal and habitat factors affected predation risk. The increased success of higher nests could be associated with some aspect of rat snakes’ climbing ability. In combination with results for two other species studied previously at the same location, our results for cardinals suggest that the specific seasonal pattern of nest success expected for a given bird species will depend on how its nesting season coincides with predator activity. Determining the generality of seasonal variation in predator behavior as a mechanism for producing seasonal patterns of avian nest success will require additional studies that investigate birds and their nest predators simultaneously.     

Nest building by a neotropical social wasp using Cecropia trichomes as main construction material (Hymenoptera,Vespidae, Polistinae)

Nest architecture is such a splendid product of social wasp behavior, there being a large diversity of nest types in the Neotropical fauna. Charterginus is a small wasp genus with six species recorded from Honduras through South America, and one species C. fulvus is notable for normally making nests with a very peculiar star shape. Few behavioral traits of this genus have been described, an exception being a record of cleptobiosis between Charterginus species and Azteca ants on Cecropia trees in Amazonia and Central America. Here we describe behavioral traits of C. fulvus related to the construction process of the nest envelope and the materials used, discussing the apparent dependency of this wasp species on resources provided by Cecropia trees. Experimental induction of reconstruction of the envelope resulted in a different oval regular shape, without the characteristic hollow points. Evidence is also presented of the use by this wasp of lichen components to make the white spots typically seen on nests.

     

Manipulation of oviposition choice of the parasitoid wasp, Encarsia pergandiella, by the endosymbiotic bacterium Cardinium

Reproductive manipulations of hosts by maternally inherited bacterial endosymbionts often result in an increase in the proportion of infected female hosts in the population. When this involves the conversion of incipient males to genetic or functional females, it presents unique difficulties for symbionts invading hosts with sex-specific reproductive behaviours, such as the autoparasitic Encarsia pergandiella. In sexual forms of this species, female eggs are laid in whitefly nymphs and male eggs are laid in conspecific or heterospecific parasitoids developing within the whitefly cuticle. Further, eggs laid in the 'wrong' host do not ordinarily complete development. This study explored the role of a bacterial symbiont, Cardinium, in manipulating oviposition behaviour in a thelytokous population of E. pergandiella. Oviposition choice was measured by the number and location of eggs deposited by both infected and uninfected adult waSPS in arenas containing equal numbers of hosts suitable for the development of male and female waSPS. Uninfected waSPS included antibiotic-treated female waSPS and (untreated) daughters of antibiotic-treated female waSPS. The choices of waSPS in the thelytokous population treatments were compared with those of a conspecific sexual population. We found that offspring of antibiotic-cured thelytokous waSPS reverted to the behaviour of unmated sexual waSPS, laying their few eggs almost exclusively in hosts appropriate for male eggs. Infected thelytokous waSPS distributed their eggs approximately evenly between host types, much like mated sexual female waSPS. The antibiotic-treated female waSPS exhibited choices intermediate to waSPS in the other two treatments. The change in the observed behaviour appears sufficient to allow invasion and persistence of Cardinium in sexual populations. Lastly, our results suggest a reduction in host discrimination as a possible mechanism by which Cardinium influences this change.     

Control of Liriomyza langei on chrysanthemum by Diglyphus isaea produced with a standard or modified parasitoid rearing technique

Abstract: Overproduction of male parasitoids during mass rearing will increase costs for biological control because wasp shipments contain fewer females and only females kill hosts directly. We have developed a rearing technique capable of significantly reducing male‐biased sex ratios in Diglyphus isaea (Walker) (Hym., Eulophidae), a commercially reared parasitoid of agromyzid leafminers. In this study, we examined the effect of rearing technique on the efficacy of D. isaea for biological control of Liriomyza langei Frick (Dip., Agromyzidae) on chrysanthemum, Dendranthema grandiflora Tzvelev var. ‘Miramar’. We produced D. isaea on mixtures of small and large hosts (our modified technique) or on only large hosts (simulating commercial mass‐rearing) and compared: (1) control of L. langei with D. isaea produced by the two rearing techniques, and (2) damage and yield of unprotected and protected plants. The two rearing techniques produced similar numbers of waSPS per rearing cohort, but the ‘modified’ technique reduced the proportion of males by approximately 13%. The two techniques also produced females of similar size, but the ‘modified’ technique produced smaller males. In greenhouse trials simulating leafminer infestations of potted chrysanthemums during commercial production, we found no significant differences between the levels of control obtained by releasing identical numbers and sex ratios of adult waSPS produced by either rearing technique. Mine counts on plants protected by waSPS of either rearing history were similar and around 30–70% less than unprotected plants during most of the 11‐week crop cycle. At crop harvest, more than half of the foliage on protected plants was undamaged compared with <10% on unprotected crops. Damage to the flower stems of protected plants was relatively light in the top half of the canopy compared with the bottom half. Protected plants were around 10–15% taller and produced twice as many flower buds compared with unprotected plants. Our ‘modified’ rearing technique can reduce overproduction of males in D. isaea with no compromise in biological control efficacy. Adoption of our rearing technique by commercial insectaries could reduce implementation costs for not only D. isaea but also other parasitoids that show host‐size‐dependent sex allocation.     

Interspecific nest destruction in the Tropical Kingbird Tyrannus melancholicus: kleptoparasitism or competition?

Bird nest destruction and nest material kleptoparasitism (i.e., the theft of nest material from other bird’s nests) are poorly documented behaviors, and little is known about the parasite species and their hosts. Here, I present the first account of nest material kleptoparasitism in the Tropical Kingbird (Tyrannus melancholicus) followed by nest destruction, which occurred on a Variegated Flycatcher nest (Empidonomus varius). I explore the implications of these behaviors for both the kleptoparasite and the victim species and, due to the lack of basic information on the general behavior of both species, I point out some directions to guide future researches on the subject.

     

Determination of some structural features of the nest paper materials of Dolichovespula Saxonica Fabricius, 1793 (Hymenoptera: Vespinae) in Turkey

The purpose of this paper is to identify the nest materials, some physical characteristics and the elemental composition of the nest of Dolichovespula saxonica (Fabricius, 1793). The nest surfaces were observed with a stereomicroscope and scanning electron microscope (SEM). In the inner surface of the D. saxonica nest the medium thickness of the fibers in the envelope and comb varied between 7.14 and 26.9 μm, respectively and averaged 16.4 μm. In the outer surface of the nest the medium thickness of the fibers in the envelope and comb were between 3.52 and 5.70 μm, respectively and averaged 4.63 μm. The nitrogen concentration of the nest of D. saxonica was 0.616% and the amount of protein was 3.08%. The percentages of the fibers, saliva, oil and the water absorption capacity were calculated as 67–70%, 23–30%, 12–18% and 110–140%, respectively. However, the amount of the element Cadmium (Cd) in the nest was found to have a value of 0.2 ppm. The major compounds of wasp nests are plant fibers, saliva and oil. However, the concentrations and ratios of the nest material compounds depend on the plant variety, place of origin, and time of harvest as well as on the processing and saliva conditions. The colors of the nest are beige, cream and grey with long dark brown lines. As a result of our study, we have found that the rates and quantities of physical characteristics, elemental composition and the fibers in the envelope and comb of the nest of D. saxonica change with environmental conditions.     

Behavior of the Avian Parasite Philornis downsi (Diptera: Muscidae) in and Near Host Nests in the Galapagos Islands

The Avian Vampire Fly, Philornis downsi, has invaded the Galapagos Islands, where it causes high mortality of endemic and native landbird species, including most species of Darwin’s finches. Control methods are under development, but key information is missing about the reproductive biology of P. downsi and the behavior of flies in and near nests of their hosts. We used external and internal nest cameras to record the behavior of P. downsi adults within and outside nests of the Galapagos Flycatcher, Myiarchus magnirostris, throughout all stages of the nesting cycle. These recordings showed that P. downsi visited flycatcher nests throughout the day with higher fly activity during the nestling phase during vespertine hours. The observations also revealed that multiple P. downsi individuals can visit nests concurrently, and that there are some interactions among these flies within the nest. Fly visitation to nests occurred significantly more often while parent birds were away from the nest than in the nest, and this timing appears to be a strategy to avoid predation by parent birds. We report fly mating behavior outside the nest but not in the nest cavity. We discuss the relevance of these findings for the adaptive forces shaping P. downsi life history strategies as well as rearing and control measures.

     

Spatial scale of observation affects α, β and γ diversity of cavity-nesting bees and wasps across a tropical land-use gradient

Aim Anthropogenic changes in land use may have major consequences for global biodiversity. However, species diversity is determined by a suite of factors that may affect species differently at different spatial scales. We tested the combined effects of land use and spatial scale on α, β and γ diversity in the tropics using experimental communities of cavity‐nesting bees and waSPS (Hymenoptera: Aculeata). We aimed to determine whether: (1) land‐use intensity negatively affects species richness of cavity‐nesting Hymenoptera, (2) β diversity, both within and between plots, is higher in more natural systems, (3) species richness of flowering herbs correlates positively with species richness of Hymenoptera within and across habitats, (4) richness of cavity‐nesting Hymenoptera in highly modified habitats declines with increasing distance from natural or semi‐natural habitats, (5) the effects of land use, herb diversity and forest distance on Hymenoptera α and β diversity vary at different spatial scales, and (6) bees and waSPS respond to land use in a similar way. Location Manabi, south‐west Ecuador. Methods We examined diversity (species richness) within 48 plots of five habitat types that comprised a gradient of decreasing agricultural intensity from rice and pasture to coffee agroforests, unmanaged abandoned agroforests and forest fragments, using standardized nesting resources for reproducing communities of cavity‐nesting bees and waSPS. Results (1) Land use significantly affected α diversity of trap‐nesting bees and waSPS at the subplot (per trap) scale, but not subplot β diversity or plot‐scale species richness (γ diversity). (2) Beta diversity was surprisingly higher between plots within a land‐use type than between land‐use types. (3) Species richness of bees and waSPS increased with diversity of flowering herbs at the subplot (trap) scale only. (4) Forest distance correlated positively with bee species richness at the plot scale only. (5) Land use, herb diversity and forest distance each showed significant correlations with bee and wasp diversity at only one spatial scale. (6) Despite differences in life history, bees and waSPS responded to land‐use intensity in a similar way. Main conclusions The effects of land use on species richness were highly dependent on spatial scale. Subplot‐scale analyses showed that rice and pasture contained the highest species diversity, whereas plot‐scale analyses showed no significant difference in the diversity of different land‐use types. We emphasize caution in the estimation of biodiversity at only one spatial scale, and highlight the surprisingly large contribution of managed land to the regional biodiversity of these species.     

Nutrient Dynamics of a Swarm-founding Social Wasp Species,Polybia occidentalis (Hymenoptera: Vespidae)

The kinds, rates of acquisition, inter-individual transfers, and intra-colonial movements of nutrients were ascertained for the advanced eusocial paper wasp Polybia occidentalis (Olivier). Foraging worker wasps (“foragers”) bring arthropod prey and nutritive liquids (“nectar”) to the nest, and these are usually transferred to nest workers (“receivers”) on the outer nest envelope. Arthropod prey items, which are brought intact to the nest, are malaxated by one or more receivers before being fed to larvae; malaxating adults retain a portion of the hemolymph for their own nourishment. Nectar is usually transferred (via adult-adult torphallaxis) from foragers to receivers on the nest envelope; some nectar is given to larvae, and all adults that imbibe it retain at least some for their own nourishment. Larval saliva of P. occidentalis contains glucose, protein, and free amino acids and so is highly nutritive; the nutrient content of the saliva closely resembles that of the saliva of other social wasp taxa. Adult wasps imbibe larval saliva, but very little is apparently transferred by those adults (via trophallaxis) to nestmates. Brood cannibalism was infrequent during this study. Adult worker and male wasps possess chymotrypsin-like and trypsin-like enzyme in their midguts and so are likely capable of protein digestion. The midgut proteases show an age-correlated variation in concentration. Pulp foragers are significantly smaller and lighter in weight than are receivers.     

Predator feeding vibrations encourage mosquito larvae to shorten their development and so become smaller adults

1. Water‐borne predator kairomones are known to allow mosquito larvae to detect and identify the presence of a specific predator, so that they can deploy defences tailored to that predator. Kairomones, however, have limitations, and detection of specific water‐borne vibrations produced by a predator would allow fine‐tuning of their anti‐predator defences. 2. Larvae of the mosquito Culiseta longiareolata have previously been shown to recognise the specific vibration pattern of a feeding dragonfly nymph and respond by altering their feeding behaviour from active bottom‐scraping to a more passive surface filter‐feeding, while other water vibrations did not produce this response. Culex perexiguus larvae also responded, but to a much lesser extent. 3. In this study, C. perexiguus larvae responded strongly to dragonfly vibrations by reducing their larval duration from 9.8 to 8.7 days, but this resulted in significantly smaller (and thus probably less successful) adults. However, Culiseta longiareolata larvae did not alter their larval duration in response to dragonfly vibrations.     

Major benefits of guarding behavior in subsocial bees: implications for social evolution

Parental care is a behavior that increases the growth and survival of offspring, often at a cost to the parents' own survival and/or future reproduction. In this study, we focused on nest guarding, which is one of the most important types of extended parental care; we studied this behavior in two solitary bee species of the genus Ceratina with social ancestors. We performed the experiment of removing the laying female, who usually guards the nest after completing its provisioning, to test the effects of nest guarding on the offspring survival and nest fate. By dissecting natural nests, we found that Ceratina cucurbitina females always guarded their offspring until the offspring reached adulthood. In addition, the females of this species were able to crawl across the nest partitions and inspect the offspring in the brood cells. In contrast, several Ceratina chalybea females guarded their nests until the offspring reached adulthood, but others closed the nest entrance with a plug and deserted the nest. Nests with a low number of provisioned cells were more likely to be plugged and abandoned than nests with a higher number of cells. The female removal experiment had a significantly negative effect on offspring survival in both species. These nests frequently failed due to the attacks of natural enemies (e.g., ants, chalcidoid wasps, and other competing Ceratina bees). Increased offspring survival is the most important benefit of the guarding strategy. The abandonment of a potentially unsuccessful brood might constitute a benefit of the nest plugging behavior. The facultative nest desertion strategy is a derived behavior in the studied bees and constitutes an example of an evolutionary reduction in the extent of parental care.     

Floating and fidelity in nest visitation byCrawfordapis luctuosa (Hymenoptera: Colletidae)

We studied nest visitation behavior of the ground-nesting beeCrawfordapis luctuosa (Colletidae) at the Monteverde Cloud Forest Preserve, Puntarenas Province, Costa Rica. Some females entered many nests, while others consistently entered only one nest. Multiple nest entry was exhibited by bees we called floaters, and those bees that consistently entered only one nest were provisioning bees. Provisioning bees abandoned their old nests after provisioning periods and became nonprovisioning bees that floated over the nesting area. Floating behavior was a nest-searching behavior typified by oscillating flights just above the ground (<15 cm). Floaters investigated available nests and were not observed to interact aggressively with nest owners. Upon establishing a new nest, floaters became provisioning bees.     

Hissing in bumblebees: an interspecific defence signal

Summary: Bumblebees (Bombus terrestris) react to disturbances within the nest by a conspicuous hissing sound. The sound is characterised by a high intensity in the ultrasonic frequency range. It is elicited by vibrations of the nest and by mammalian breath and artificial air currents containing CO₂. Domestic mice entering a bumblebee nest elicit these sounds and retreat immediately in response to the bumblebees' signal. It is concluded that the hissing sounds serve as aposematic warning signals aimed at predators entering the nest.     

Do Birds Alter Levels of Parental Investment Based on Nest‐Site Habitat Features?

Many habitats have undergone rapid changes over the past century as a result of anthropogenic activities. Organisms can respond to changes in their environment in many ways, including how much they invest in a given reproductive bout. Optimality theory and life history theory together have provided a framework for understanding how individuals make decisions about the risks and rewards of investing high levels of resources into their offspring within the context of current vs. future reproduction. Shrubland birds in the United States often breed in habitat that has been impacted by humans to varying degrees and provide an ideal system for examining whether organisms alter their levels of parental investment based on the habitat around the nest site. In this study, we assessed levels of nest‐defense behavior during a simulated nest predation event in four shrubland birds: American robins (Turdus migratorius), gray catbirds (Dumetella carolinensis), brown thrashers (Toxostoma rufum), and northern cardinals (Cardinalis cardinalis). We found that thrashers and catbirds exhibited significantly higher levels of nest defense compared to robins and cardinals and that birds with larger broods acted more aggressively in defending them. We also found that thrashers acted less aggressively as the proportion of shrubland around the nest increased and as the proportion of developed land around the nest decreased and that cardinals acted less aggressively as the proportion of developed land around the nest increased. These patterns suggest that nest‐defense behavior can covary with features of the landscape surrounding the nest, but that the factors shaping that behavior can differ by species.     

Rules for Nest Sanitation in a Social Spider Mite, Schizotetranychus miscanthi Saito (Acari: Tetranychidae)

Waste management behavior is essential to achieve nest sanitation that is highly inferential on the evolution of group living because nest waste is an inevitable cost. However, how group living animals dispose of waste has not attracted much attention. Schizotetranychus miscanthi Saito is a social spider mite infesting a perennial grass (Miscanthus sinensis Anderss), in which all nest members tend to defecate at specific sites. We investigated the mechanisms by which the individuals select the site of defecation. The results show that nest members defecate at only one site inside the nest, and that waste management is maintained by two simple rules. First, mites defecate near the nest entrances if no volatile chemical cues are available, and secondly, when chemical cues are available from feces deposited previously, they defecate at this site. We discuss the adaptive significance of these mechanisms, as well as their role in the evolution of sociality in mites.     

Colony Membership, Division of Labor, and Genetic Relatedness Among Females of Colonies of Eustenogaster fraterna (Hymenoptera, Vespidae, Stenogastrinae)

To compare the social structure of primitively social wasps with that of communal breeding vertebrates, we used a new technique based on micro videocameras applied to the nest envelope to study the organization of behavior in Malaysian colonies of the stenogastrine wasp Eustenogaster fraterna. The reproductive division of labor in this species appears to be different from that reported so far in other species of Stenogastrinae: it is at a very primitive stage because the helpers work less hard and take fewer risks than the egg-layers. Nevertheless, the very low-risk tasks performed by the helpers (nest guarding and supply of abdominal secretion to the young larvae) are important for the colonies. Behavioral characters and ovarian development of the helpers suggest that females are only temporary helpers and that they wait to start their own production of offspring in the hope of inheriting the nest. Females of the same colony can be highly related, but in some colonies we found low-related individuals. The social organization of these wasps resembles that of vertebrate groups with helpers at the den, i.e., in the small number of individuals, the division of labor with limited reproductive inhibition, and the prolonged external work of the reproductive individuals. However, the main drive to sociality in these insects appears to be different, being based mainly on problems connected with short adult life and long immature brood development.