Abdominal grooming in the cockroach: Development of an adult behavior

Chemical or tactile irritants delivered to the dorsomedial region of the abdomen of the cockroach Periplaneta americana. evoke a complex grooming response. In larvae the response consitsts of extension of all six legs and arching of the abdomen which is rubbed against any solid surface presented. In adults, leg extension and arching are accompanied by side to side wagging of the abdomen and rapid scissoring of the wings.In some decapitated late instar larvae, abdominal wagging behavior can be evoked by chemical or tactile stimulation of the dorso-medial region of the abdomen. The form of the wag is somewhat different in these animals than in the adults, and it occurs at a lower frequency.Neuronal circuitry underlying the rhythmic wagging response of the adult may therefore be laid down or made functional in the mid- to late-larval stages. The wagging behavior is not normally expressed until the final ecdysis.A population of sensory setae is found on the abdomen at all stages of development, and some of these are presumed to trigger the grooming behavior when stimulated. The morphology and distribution of some of the adult receptors differs from some of the larval receptors.All larvae, including those late-instar individuals which show an adult-like response (wagging) have identical receptors on the abdomen in terms of morphology, distribution, and general responsiveness. Thus, no obvious changes in abdominal sensory receptors are correlated with the emergence of the wagging behavior. Anatomical and/or functional changes within the central nervous system are most likely responsible for the emergence of adult wagging behavior.     

Predatory bug <Emphasis Type="Italic">Picromerus bidens</Emphasis> communicates at different frequency levels

The Asopinae (Heteroptera: Pentatomidae) are a subfamily of stinkbugs with predaceous feeding habits and poorly understood communication systems. In this study we recorded vibratory signals emitted by Picromerus bidens L. on a non-resonant substrate and investigated their frequency characteristics. Males and females produced signals by vibration of the abdomen and tremulation. The female and male songs produced by abdominal vibrations showed gender-specific time structure. There were no differences in the temporal patterns of male or female tremulatory signals. The signals produced by abdominal vibrations were emitted below 600 Hz whereas tremulatory signals had frequency ranges extending up to 4 kHz. Spectra of male vibratory signals produced by abdominal vibrations contained different peaks, each of which may be dominant within the same song sequence. Males alternated with each other during production of rivalry signals, using different dominant frequency levels. We show that the vibratory song repertoire of P. bidens is broader than those of other predatory stinkbugs that have been investigated. The emission of vibrational signals with different dominant frequencies but the same production mechanism has not yet been described in heteropteran insects, and may facilitate location of individual sources of vibration within a group.     

<Emphasis Type="Italic">Polistes japonicus</Emphasis> (Hymenoptera,Vespidae) queens monopolize ovipositing but are not the most active aggressor in dominant-subordinate interactions

In order to elucidate the dominant–subordinate relationship between the foundress and workers, five colonies of the paper wasp Polistes japonicus were observed in a netted and covered cage located outdoors. The number of workers in each colony ranged from four to eight. Workers were divided into first and second broods. Abdominal wagging and ovipositing were performed almost exclusively by the foundress throughout colony development. However, an analysis of aggressive encounters indicated that although the foundress hardly received dominance behaviors (aggression) from workers, it lacked either partially or completely the following characteristics of the queen that are usually seen in paper-wasp colonies with independent-founding queens (except in one colony that produced no second brood): the queen being socially dominant over any worker (the queen had more wins than losses in one-on-one dominance contests with any worker), exhibiting the highest frequency of dominance behaviors, and directing dominance behaviors primarily toward the socially most-dominant worker. In particular, during the mixed-brood period (when all first- and second-brood workers were present on the nest) the foundress hardly exhibited dominance behaviors toward socially dominant workers (mainly second brood) but frequently directed dominance behaviors toward socially subordinate workers (mainly first brood). The foundress disappeared in two colonies before the reproductives emerged; in these colonies the socially most-dominant worker inherited the colony and laid many eggs. The frequency of abdominal wagging by these two foundresses decreased during colony development, while it did not in the other colonies. This suggests that abdominal wagging provides information about the vigor of the performer. The superseder was socially dominant over all other workers, but spent little time wagging its abdomen and allowed some workers to lay eggs.     

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.     

Scraping Sounds Produced by a Social Wasp (Asteloeca ujhelyii, Hymenoptera: Vespidae)

A distinct behavior performed by workers of the social wasp Asteloeca ujhelyii is described: guard waSPS, sitting outside of the nest around the entrance hole, scratch the nest envelope with their forelegs, thereby producing an audible ‘scraping sound’. Field observations revealed a relationship between the occurrence of the scraping behavior and the occurrences of waSPS entering and leaving the nest. The scraping was experimentally reproduced in the laboratory by moving a dissected wasp's leg parallel to the plane of the nest envelope. The resulting substrate‐borne vibrations propagate very well over a distance of a few centimeters. The amplitude of these vibrations depends on the velocity of the scraping movements. The possible role of the scraping behavior in the waSPS’ communication is discussed.     

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.

     

The Role of the Vibration Signal during Nest‐Site Selection by Honey Bee Swarms

The vibration signal may influence nest‐site selection by honey bee swarms by enhancing scouting and recruitment. We investigated this hypothesis by comparing (1) the number of nest sites and the distances communicated by nest‐site dancers on swarms from which vibrators were and were not removed and (2) the behavior of scouts visiting higher‐quality (HQ) and lower‐quality (LQ) nest boxes. The removal of vibrators from swarms did not alter the number of nest sites investigated, the distances traveled to nest sites, or the time required to select a new nest cavity. In contrast, vibrator removal tripled the time required for swarms to achieve liftoff after a cavity had been selected, although all swarm eventually became airborne and moved to a new site. About 14% of the scouts that visited the HQ and LQ nest boxes performed vibration signals; however, nest‐box quality did not influence the tendency to produce the signal or intermix vibration signals and recruitment dances. However, we did find a significant, positive correlation between overall levels of vibration signal activity and nest‐site recruitment during the house‐hunting process. When viewed in concert, our results suggest that the vibration signal contributes to the house‐hunting process by operating in a non‐specific manner that may enhance scouting and recruitment in general during nest‐site selection and facilitate rapid swarm liftoff after a new nest site has been chosen. The vibration signal is therefore a component in the cascade of communication signals that orchestrate house‐hunting and colony relocation decisions.     

Foraging vibration signals attract foragers and identify food size in the drywood termite, <Emphasis Type="Italic">Cryptotermes secundus</Emphasis>

Information gathering and communication behaviour has evolved within constraints of size, physiology and ecology of the animal. Due to these constraints, small herbivorous insects are likely to use substrate borne vibrations for information gathering and communication. Although such signals have been characterised in many types of insects, including group-living insects, they are poorly known in termites.We showed that the Australian drywood termite Cryptotermes secundus could determine the size of wooden blocks by using the vibrations generated during foraging. The termites behaved differently in choice experiments when artificially generated vibration signals were played compared with natural recordings, indicating that these termites can discriminate the source of the vibration as well. AT-maze experiment showed that the termites were attracted to the natural recordings of feeding termites, suggesting that vibrations are important in communication during foraging as well as food resource assessment. Combining the effects of food size preference and attraction to other termites explained differences in behaviour between artificially generated vibration signals compared with natural recordings. This study demonstrates that termites use substrate borne vibrations for information gathering and communication as predicted. Received 21 March 2007; revised 19 June and 7 August 2007; accepted 20 August 2007.     

Vibration Signal Modulates the Behavior of House-hunting Honey Bees (Apis mellifera)

Honey bees ( Apis mellifera ) in house-hunting swarms perform vibration signals (dorsoventral abdominal vibration (DVAV)) of 18.05 ± 0.45 Hz for 1.36 ± 0.23 s throughout the house selection process. These signals are performed by a specialized subset of bees, most of whom never perform recruitment dances to nest sites. Individuals repeatedly vibrate others. The patterns of vibration signal performance are consistent with the hypothesis that it serves to activate bees for take-off, but may also activate bees to scout for nest sites.     

Oviposition behavior of Anagrus nigriventris,an egg parasitoid of beet leafhopper, Circulifer tenellus

Oviposition behavior of Anagrus nigriventris,a parasitoid of the eggs of the beetleafhopper,Circulifer tenellus, wasdescribed on sugar beet. Ovipositor probes ofrelatively long duration were accompanied by a periodof abdominal vibrations toward the end of the probe. These periods began as high frequency, low amplitudevibrations in the abdomen, and climaxed as a tremblingof the whole body in an up and down direction.Oviposition by the parasitoid was associated with theoccurrence of abdominal vibrations during a probe andwith probe durations 50 s; however thepresence/absence of abdominal vibrations during aprobe was considered a more reliable indicator ofoviposition than was a threshold probe duration of 50s. The majority of probes (63% of all probes) were inempty plant tissue, lasted 15 s, and were notassociated with abdominal vibrations. While probeswithout abdominal vibrations at host egg sites (14%of all probes) lasted an average of 48 s, probes withabdominal vibrations at host egg sites (23% of allprobes) lasted an average of 102 s, and all were 50s. It is hypothesized that the relative frequency ofthe 3 types of probes could be affected by the degreeof wasp experience, by the level of host cues on thesubstrate, and by the relative importance of ovipositor probing (vs. antennation) in the hostdetection process. Data from the study suggest thatA. nigriventris is able to discriminate againstpreviously attacked host eggs.     

Multisegmental motor activity in the segmentally restricted gin trap behavior in Manduca sexta pupae

Stimulation of sensory neurons innervating hairs in the gin traps on the abdomen of Manduca sexta pupae evokes a rapid bending of the abdomen that is restricted to one or more of the three articulating posterior segments. However, electrical stimulation of the gin trap sensory nerve in an isolated abdominal nerve cord evokes characteristic motor neuron activity in every abdominal segment. To determine if the segmentally distributed motor activity also occurred in intact animals and how it contributed to the segmentally restricted reflex movement, mechanical stimulation of the sensory hairs in intact animals was used to evoke reflex responses that were recorded as electromyograms synchronized with video recordings of the behavior. Motor activity was monitored during movements to determine if there was activity in many segments when the movement was restricted to one segment. Coordinated muscle activity was evoked throughout the abdomen in response to stimulation of any of the three gin traps, even when movement was restricted to one segment. Differences in the timing of ipsilateral and contralateral motor activity among segments allowed the closing of gin traps to be segmentally restricted. These findings suggest that the neural circuit underlying the gin trap reflex is distributed throughout the abdominal nerve cord. This network generates a complex, yet coordinated, motor pattern with muscular activity in many abdominal segments that produces a localized bending reflex. Accepted: 10 January 1997     

The effects of heterospecifics and climatic conditions on incubation behavior within a mixed‐species colony

Parental incubation behavior largely influences nest survival, a critical demographic process in avian population dynamics, and behaviors vary across species with different life history breeding strategies. Although research has identified nest survival advantages of mixing colonies, behavioral mechanisms that might explain these effects is largely lacking. We examined parental incubation behavior using video‐monitoring techniques on Alcatraz Island, California, of black‐crowned night‐heron Nycticorax nycticorax (hereinafter, night‐heron) in a mixed‐species colony with California gulls Larus californicus and western gulls L. occidentalis. We first quantified general nesting behaviors (i.e. incubation constancy, and nest attendance), and a suite of specific nesting behaviors (i.e. inactivity, vigilance, preening, and nest maintenance) with respect to six different daily time periods. We employed linear mixed effects models to investigate environmental and temporal factors as sources of variation in incubation constancy and nest attendance using 211 nest days across three nesting seasons (2010–2012). We found incubation constancy (percent of time on the eggs) and nest attendance (percent of time at the nest) were lower for nests that were located < 3 m from one or more gull nest, which indirectly supports the predator protection hypothesis, whereby heterospecifics provide protection allowing more time for foraging and other self‐maintenance activities. To our knowledge, this is the first empirical evidence of the influence of one nesting species on the incubation behavior of another. We also identified distinct differences between incubation constancy and nest attentiveness, indicating that these biparental incubating species do not share similar energetic constraints as those that are observed for uniparental species. Additionally, we found that variation in incubation behavior was a function of temperature and precipitation, where the strength of these effects was dependent on the time of day. Overall, these findings strengthen our understanding of incubation behavior and nest ecology of a colonial‐nesting species.     

Effect of alarm calling by male Red‐winged Blackbirds on nestling begging and female provisioning behavior

ABSTRACT Nestling begging and parental provisioning can attract nest predators and reduce reproductive success, so parents and their offspring might be expected to respond adaptively by minimizing predator‐attracting cues when predators threaten nests. Male Red‐winged Blackbirds (Agelaius phoeniceus) are well known for their antipredator alarm calls that contain information about the approach of potential nest predators. We examined the begging behavior of nestlings and the provisioning behavior of females in response to antipredator alarm calls of males to test the adaptive response hypothesis. Playback experiments provided no evidence that alarm calls function to switch off vocal begging; nestlings were equally likely to beg vocally during playback and control periods. Video recordings showed that male alarm calling had no significant effect on inappropriate vocal begging (in the absence of an adult), but significantly reduced the incidence of spontaneous calling (in the absence of begging). Adult females responded to male antipredator alarm calls by delaying their provisioning visits. In addition, although having no significant effect on use of nest‐arriving calls by females, male alarm calling significantly reduced their use of nest‐leaving calls. We conclude that nestling and female Red‐winged Blackbirds respond to male alarm calls in ways that might reduce the risk of predation, but nestlings beg vocally when females arrive to feed them, regardless of male alarm calling, perhaps to avoid a competitive disadvantage with broodmates.     

Does body size predict the buzz‐pollination frequencies used by bees?

Body size is an important trait linking pollinators and plants. Morphological matching between pollinators and plants is thought to reinforce pollinator fidelity, as the correct fit ensures that both parties benefit from the interaction. We investigated the influence of body size in a specialized pollination system (buzz‐pollination) where bees vibrate flowers to release pollen concealed within poricidal stamens. Specifically, we explored how body size influences the frequency of buzz‐pollination vibrations. Body size is expected to affect frequency as a result of the physical constraints it places on the indirect flight muscles that control the production of floral vibrations. Larger insects beat their wings less rapidly than smaller‐bodied insects when flying, but whether similar scaling relationships exist with floral vibrations has not been widely explored. This is important because the amount of pollen ejected is determined by the frequency of the vibration and the displacement of a bee's thorax. We conducted a field study in three ecogeographic regions (alpine, desert, grassland) and recorded flight and floral vibrations from freely foraging bees from 27 species across four families. We found that floral vibration frequencies were significantly higher than flight frequencies, but never exceeded 400 Hz. Also, only flight frequencies were negatively correlated with body size. As a bee's size increased, its buzz ratio (floral frequency/flight frequency) increased such that only the largest bees were capable of generating floral vibration frequencies that exceeded double that of their flight vibrations. These results indicate size affects the capacity of bees to raise floral vibration frequencies substantially above flight frequencies. This may put smaller bees at a competitive disadvantage because even at the maximum floral vibration frequency of 400 Hz, their inability to achieve comparable thoracic displacements as larger bees would result in generating vibrations with lower amplitudes, and thus less total pollen ejected for the same foraging effort.     

RNAi analysis of nubbin embryonic functions in a hemimetabolous insect,Oncopeltus fasciatus

SUMMARY Although the expression of the POU homeodomain gene nubbin (nub) has been examined in several arthropod species, its function has been studied only in Drosophila. Here, we provide the first insight into functional roles of this gene in a hemimetabolous insect species, Oncopeltus fasciatus. The analysis of its function using RNAi resulted in the altered morphology of antennae and labial tubes in the head, legs in the thorax, and, most notably, the growth of ectopic appendages originating from abdominal segments A2–A6. This change in the morphology of the abdomen can largely be attributed to the altered expression patterns of two hox genes, Ubx and abd‐A, in RNAinub embryos. First, abd‐A expression is completely abolished in A3–A6. Second, weak Ubx expression expands posteriorly to encompass novel domains in A2 and A3. Concomitant with these changes, limbs on A2 and A3 are small and less developed, whereas limbs on A4–A6 are large thoracic‐like legs. These results show that nub function is necessary for normal abd‐A expression and thus plays a critical role in suppressing leg formation on the abdomen. The loss of this regulation leads to upregulation of Distal‐less, and subsequent development of appendages. In Drosophila, however, abd‐A expression is unaffected in a nub‐depleted background, indicating that no such regulatory relationship exists between these two genes in the fruit fly. These differences reveal that variation exists in the genetic mechanisms that maintain an ancient insect feature, the limbless abdomen.     

Great Spotted Cuckoos Frequently Lay Their Eggs While Their Magpie Host is Incubating

Species that suffer from brood parasitism face a considerable reduction in their fitness which selects for the evolution of host defences. To prevent parasitism, hosts can mob or attack brood parasites when they approach the host nest and block the access to the nest by sitting on the clutch. In turn, as a counter‐adaptation, brood parasites evolved secretive behaviours near their host nests. Here, we have studied great spotted cuckoo (Clamator glandarius) egg‐laying behaviour and defence by their magpie (Pica pica) hosts inside the nest using continuous video recordings. We have found several surprising results that contradict some general assumptions. The most important is that most (71%) of the parasitic events by cuckoo females are completed while the magpie females are incubating. By staying in the nest, magpies force cuckoo females to lay their egg facing the high risk of being attacked by the incubating magpie (attack occurred in all but one of the events, n = 15). During these attacks, magpies pecked the cuckoo violently, but could never effectively avoid parasitism. These novel observations expand the sequence of adaptations and counter‐adaptations in the arms race between brood parasites and their hosts during the pre‐laying and laying periods.     

Interpopulation Comparisons of Antipredator Defense Behavior of the Thorn‐Tailed Rayadito (Aphrastura spinicauda)

The high impact of predators on breeding success has favored the evolution of diverse behavioral strategies that enhance both individual survivorship and reproductive success. Self‐ and nest‐defense against predators are inter‐related behaviors that vary according to life history traits and the risks involved in defense. In addition, interpopulation differences in the composition of predator guilds, and hence predation pressures, may result in geographic variation in antipredator defense strategies. It is generally accepted that the absence of predators could drive the loss of antipredator behavior. However, it is unclear how species respond if one type of predator (e.g., a specialized nest predator) is absent but others are present. The multipredator hypothesis suggests that the absence of only a few predators is not sufficient to drive a change or loss of antipredator behavior in a species. We examined interpopulation variation in defense behavior in the thorn‐tailed rayadito (Aphrastura spinicauda), a suboscine bird inhabiting a wide latitudinal range in southern South America. In populations where nest predators were either present or absent, we examined the responses of rayaditos to an adult predator (an owl) and to a nest predator (a marsupial). Owl‐defense behavior involved more intense and longer responses than marsupial‐defense. This suggests that adult rayaditos may allocate more energy to defend themselves than their young. However, because the presence of adult predators near the nest also prevents parents from feeding the nestlings, owl‐defense may simultaneously represent a form of nest‐defense. No differences in marsupial‐defense were found among the three sampled populations, despite the absence of native mammalian nest predators in one population. The lack of variation in nest‐defense behavior provides some support for the multipredator hypothesis, although the high interpopulation gene flow in this species could also contribute to this behavior's maintenance.     

Nest Hydrocarbons as Cues for Philopatry in a Paper Wasp

Philopatric behavior has been demonstrated in a wide taxonomic spread of animals. In temperate environments, overwintered Polistes wasp foundresses often return to their natal nest prior to initiating colony construction. Previous research has shown that these spring foundresses can identify the natal nest in the absence of landmark and gross morphological cues. Hydrocarbons are essential recognition cues for Polistes nest and nestmate discrimination, but cuticular hydrocarbon profiles can become homogenized when foundresses overwinter in mixed colony groups. We examined the hydrocarbon profiles of Polistes dominulus foundresses and nests before and after an overwintering period, and found that the hydrocarbon profiles of nests remain unique over time and that this uniqueness is influenced by the original foundresses. Our data raise the possibility that in returning to the natal nest, foundresses reacquire their colony‐specific signature, which may play a role in the formation of cooperative associations.     

Mothers vigilantly guard nests after partial brood loss: a cue of nest predation risk in a paper wasp

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Mating behavior of Aegla platensis (Crustacea, Anomura, Aeglidae) under laboratory conditions

The mating behavior of several decapod crustaceans has been extensively studied; however, this aspect of anomuran biology is still poorly known in some groups. Aeglids are the only anomurans inhabiting freshwaters, and the mating behavior of the species in this family is unknown. We provide the first account of the mating behavior of an aeglid, Aegla platensis, under laboratory conditions. The precopulatory phase was characterized by male agonistic display, male approach, and courtship. Males exhibited the agonistic display toward immature and mature females, but only physiologically mature females allowed males to approach. Male approach led to display of courtship behaviors (body vibration, thrust, body lifting, and abdomen flapping). During the copulatory phase, males and females touched each other with the antennae (antennae touch), and males positioned themselves beneath the females (supine position). Although sperm transfer was not directly observed, a “white mass” was detected among oocytes in the female abdominal chamber shortly after some copulations. Finally, in the postcopulatory phase, males guard females during the process of egg attachment. Despite their morphological similarities with other anomurans, the mating behavior of aeglids seems to be unique, and the freshwater environment appears to have an important role in driving these differences.