Post-Strike Behavior of Timber Rattlesnakes (Crotalus horridus) During Natural Predation Events

The complexity of natural environments is an important component of animal behavior, and laboratory environments often cannot reproduce that complexity. Strike‐induced chemosensory searching (SICS) is a robust phenomenon among venomous snakes that has been studied extensively in the laboratory. To date, observations of this behavior in the field have been limited largely to anecdotes; the extent to which post‐strike behaviors in the laboratory accurately reflect what occurs in nature has not been examined. In this study, I use time‐lapse video equipment in the field to record the predatory behavior of timber rattlesnakes (Crotalus horridus). This represents the first quantitative analysis of post‐strike predatory behaviors associated with natural feeding events. As in the laboratory, stereotyped post‐strike behaviors were only observed after successful strikes, and not after missed strikes. Snakes in the field were observed to proceed through the same basic behavioral stages that have been documented in the laboratory: striking prey, releasing prey immediately after strike, post‐strike immobility, location of the chemosensory trail, trail following, and prey swallowing. However, the duration of post‐strike immobility, trail location, and prey swallowing was substantially longer in field than in laboratory studies. Additionally, post‐strike immobility was significantly longer when snakes struck large prey (prey over 100 g) than when they struck small prey. Overall, these results indicate that the behavioral challenges associated with SICS may be more robust than laboratory studies have indicated.     

Oviposition Behavior of <Emphasis Type="Italic">Pheropsophus aequinoctialis</Emphasis> L. (Coleoptera: Carabidae): A Natural Enemy of <Emphasis Type="Italic">Scapteriscus</Emphasis> Mole Crickets (Orthoptera: Gryllotalpidae)

In the southeastern United States, South American Scapteriscus mole crickets are serious pests of turf and pasture grasses and vegetable seedlings. The larval stage of Pheropsophus aequinoctialis L. is a specialist predator of Scapteriscus mole cricket eggs and is currently under evaluation as a potential biological control agent. The objective of this study was to understand the oviposition behavior of P. aequinoctialis. The results indicated that in two-choice substrate oviposition arenas, female P. aequinoctialis significantly preferred to lay eggs in sand with mole cricket tunnels compared with artificially created tunnels or sand without tunnels. Physical tunnel presence influenced oviposition depth, but was not the only factor influencing oviposition. The reproductive strategy and behavior of P. aequinoctialis is discussed in relation to its specialized life history and to other carabid beetles displaying close host associations.     

Food and feeding behavior of the hoplonemertean Oerstedia dorsalis

The monostiliferous nemertean Oerstedia dorsalis was collected from eelgrass (Zostera marina) beds located along the coast of New Jersey, and feeding responses to amphipods and isopods were observed in the laboratory. Tests with 46 worms showed that they fed suctorially on Ampelisca vadorum, Ampithoe longimana, Corophium acherusicum and C. tuberculata. Corophiids were preferred. Upon contact with an amphipod, the proboscis is everted and strikes the prey on the ventral side, immobilizing it in a few minutes. The worm probes the sternal region with its head and everts its proboscis one or more times during the process. The exoskeleton is eventually penetrated by the head, and the stomach is everted into the hemocoel as a flattened funnel-like structure. Peristaltic undulations of the body signify the suctorial action that removes the living contents from the exoskeleton. The actual feeding process (from head penetration to removal of the head) takes about 7 min. O. dorsalis is only the third species within the Prosorhochmidae for which the feeding behavior has been documented. The other two are terrestrial species, and are also suctorial.     

Intraspecific variability in the tapping behavior of the deathwatch beetle,Xestobium rufovillosum (Coleoptera: Anobiidae)

Taps were recorded from 46 male and 30 female deathwatch beetles, Xestobium rufovillosum.Beetles tap by striking the frons of the head on the substrate 4–11 times, at a frequency of about 11 Hz. There were no significant differences between the sexes in the number of strikes per tap, or in the frequency of the strikes, although there was significant variation between individuals of both sexes in both of these parameters. Males usually initiate a sequence of taps, to which females reply. Females responded more readily to male beetle taps containing high strike numbers. Use of an artificial tapper showed that females responded most to taps containing at least six strikes. Females did not discriminate between male beetle taps on the basis of strike frequency, although at abnormally high (20-Hz) or low (4-Hz) frequencies produced by the artificial tapper, females were less likely to respond. Male beetles located the source of taps from the artificial tapper and did this more readily with taps of a high strike number. It is not clear why some males produce taps with fewer than six strikes, as these are unlikely to elicit a female response, and so should be the subject of adverse sexual selection.     

<Emphasis Type="Italic">Lacuna vincta</Emphasis> (Mollusca,Neotaenioglossa) herbivory on juvenile and adult <Emphasis Type="Italic">Nereocystis luetkeana</Emphasis> (Heterokontophyta,Laminariales)

Herbivory can be an important factor structuring coastal algal communities. Herbivores may preferentially graze particular algal species or tissue types. Mesograzers, despite their small size, can critically weaken kelp thalli and impact entire kelp beds. We propose that when kelp beds are composed of several kelp cohorts, mesograzers will selectively choose to inhabit younger plants and grazing activities will have a greater impact on younger plants. This study investigated the effects of grazing by the littorinid gastropod, Lacuna vincta, on different age classes of the bull kelp, Nereocystis luetkeana by (1) testing food preference of L. vincta on juvenile, first-year adult, and second-year adult Nereocystis blades in the laboratory, (2) determining substrate (blades of different ages) preference of L. vincta in the laboratory, and by (3) estimating in-situ herbivore abundances and densities on juvenile and adult Nereocystis. Results demonstrated that grazing by L. vincta produced greater damage on juvenile than older Nereocystis tissues. Although L. vincta did not select juvenile versus older kelps as substrate in the laboratory, in situ surveys showed that differences existed between age classes with higher L. vincta densities on juvenile than adult kelp. We conclude that at a local scale, L. vincta can be an important structuring factor in Nereocystis populations due to its high density and grazing ability. Handling editor: K. Martens     

Zooplankton capture by a coral reef fish: an adaptive response to evasive prey

Synopsis High-speed cinematography and video using modified Schlieren optics and laser illumination helped elicit details of prey capture mechanisms used by Chromis viridis while feeding on calanoid copepods and Artemia. Chromis viridis is capable of a ram-jaw, low-suction feeding, as well as a typical suction feeding behavior described for other species of planktivores. By adjusting the degree of jaw protrusion and amount of suction used during a feeding strike, this fish can modulate its feeding strikes according to the prey type being encountered. The ram-jaw feeding mode enables C. viridis to capture highly evasive calanoid copepods within 6 to 10 msec. The use of specialized feeding behavior for evasive prey and the ability to vary feeding behavior are adaptations for feeding on evasive prey.     

Ontogenetic changes in the ecological function of the association behavior between jack mackerel <Emphasis Type="Italic">Trachurus japonicus</Emphasis> and jellyfish

Commensal behavior of jack mackerel Trachurus japonicus (Temminck & Schlegel) with jellyfishes has been widely observed but its ecological function is still unclear. The goal of the present research is to examine the function of association behavior with jellyfish in the laboratory and in field observations with an emphasis on ontogenetic changes. In the laboratory, jack mackerel juveniles (mean standard length (SL) = 11, 19, 38, and 55 mm) were placed in 500-l polycarbonate tanks with two live moon jellyfish, Aurelia aurita (Linné), and one artificial jellyfish made of silicon. Association behavior with either live or artificial jellyfish was visually observed under the following conditions: control, presence of a predator model, before and after feeding live Artemia, 1 h and 3 h after feeding, and at night. Jack mackerel at 11 mm SL associated with both the moon jellyfish and artificial jellyfish, unrelated to the presence of a predator model or feeding. Juveniles at 19 mm associated with moon jellyfish only in the presence of a predator model. Larger juveniles associated with moon jellyfish at 1 h and 3 h after feeding. Thus the ecological function of association was proposed to develop first from school formation, next as a hiding place from predators, and then as a food source. Underwater observations of jack mackerel associating with giant jellyfish Nemopilema nomurai (Kishinouye) in two different areas in the Sea of Japan supported this hypothesis. High predation pressure from benthic piscivorous fishes in the southern area (Tsushima) may encourage association with jellyfish, whereas pressure from pelagic predators in the northern area (Maizuru) may encourage settlement to rocky reef habitats in temperate waters. Thus the jellyfish may also function as a vehicle for the northward migration of this species. Guest editors: K. A. Pitt & J. E. Purcell Jellyfish Blooms: Causes, Consequences, and Recent Advances     

Selection of Bemisia nymphal stages for oviposition or feeding,and host-handling times of arrhenotokous and thelytokous <Emphasis Type="Italic">Eretmocerus mundus</Emphasis> and arrhenotokous <Emphasis Type="Italic">E. eremicus</Emphasis>

Host-handling behavior is an important aspect of parasitoid foraging behavior. When a parasitoid encounters a potential host, the handling behavior starts with the evaluation of the host and continues if the host has been judged acceptable. Host handling is usually terminated after egg laying or host feeding and host marking. Host-handling behavior of an arrhenotokous population of two Eretmocerus species, E. mundus Mercet and E. eremicus Rose and Zolnerowich, along with a thelytokous population of E. mundus were compared under laboratory conditions. Several elements of host-handling behavior, including encountering, ascending, turning on host, descending, preening, egg laying, and host feeding were recorded. There were no correlations among the durations of these phases across parasitoid populations/species or host nymphal instars. Duration of different phases of host-handling behavior showed only slight and sometimes significant differences between different Eretmoceruspopulations/species. The actual laying of the egg had the longest duration of all host-handling behaviors, and was longer on third nymphal instars than on younger ones. Females of the three populations/species accepted the first three nymphal stages either for egg laying or for host feeding. Females spent a lot of time to make wounds in the host when preparing for host feeding, and eventually killed the host. The implications of these findings for the use of the different Eretmoceruspopulations/species in biological control are discussed.     

The influence of conspecific chemical cues on walking behavior of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> males

The influence of female and male cues on the male searching behavior of the sheep tick, Ixodes ricinus (Acari: Ixodidae), was studied under constant laboratory conditions by means of a computerized video tracking system. Males were released into an open glass arena in which one half had been exposed for 1 h to 5 freely walking unfed females or five males. The obtained track data were analyzed to reveal if male walking pattern was random or affected by cues of conspecifics left on the arena surface. The results showed that males spent significantly more time and walked a significantly longer distance in the area with female cues compared to the control area. Moreover, the walking path of males was more tortuous on the cues half than the control half. In contrast, walking behavior of males was not affected by male cues in any observed parameter. These results provide the first evidence that unfed females leave sex-specific semiochemicals on a substrate during their walk and that these cues have an effect on male searching behavior. Since this effect was not observed when female cues were 24-h old, the semiochemicals seem to either evaporate or are subject to degradation. The biological significance of these findings for mate-searching in I. ricinus males is discussed.     

Morphology and development of <Emphasis Type="Italic">Pteromalus cerealellae</Emphasis> (Ashmead) (Hymenoptera: Pteromalidae) on <Emphasis Type="Italic">Callosobruchus maculatus</Emphasis> (F.) (Coleoptera: Chrysomelidae)

Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several stored-product insect pests. Very little information has been published on its biology and development in host larvae, which typically are concealed within seeds. We documented the development of P. cerealellae within fourth instar larvae of its concealed host, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) infesting cowpea seeds. The preimaginal life stages of the parasitoid were characterized for the first time using morphological structures revealed by microscopic techniques including scanning electron microscopy. Pteromalus cerealellae produces hymenopteriform eggs and larvae. Eggs hatch into 13-segmented first instar larvae with peripneustic condition of spiracles. The larvae have simple, tusk-like mandibles, whereas the mandibles of the pupae and the adults are of the conventional toothed types. Using statistical analyses of the sizes of the larval mandibles and head capsules in conjunction with reliable characters such as the number of exuviae on the body of parasitoid larvae, cuticular folding, and excretion of the meconium, we recorded four larval instars for P. cerealellae. The data showed significant positive correlations between larval mandible lengths and widths of larval head capsules, as well as between mandible lengths and larval instars, suggesting that mandible length is a good predictor of the number of instars in P. cerealellae. Developmental time from egg to adult emergence was ∼12 d for females and ∼11 days for males at 30 ± 1°C, 70 ± 5% r.h. and 12L:12D photoperiod.     

Pathogenicity of the Entomopathogenic Fungus, <Emphasis Type="Italic">Lecanicillium muscarium</Emphasis>, against the Sweetpotato Whitefly <Emphasis Type="Italic">Bemisia tabaci</Emphasis> under Laboratory and Glasshouse Conditions

The potential for using the entomopathogenic fungus Lecanicillium muscarium to control the sweetpotato whitefly, Bemisia tabaci has been established in the laboratory by other studies. Laboratory studies however frequently overestimate the level of control achieved by biological control agents in the glasshouse. Before full-scale commercial or field development is considered, glasshouse trials are required to confirm laboratory results. Under both controlled laboratory and glasshouse conditions high mortality of second instar B. tabaci was recorded after application of L. muscarium. The potential of incorporating L. muscarium into integrated pest management strategies for the control of B. tabaci is discussed.     

Substrate regulation of serotonin and dopamine synthesis in <Emphasis Type="Italic">Drosophila</Emphasis>

In Drosophila melanogaster, serotonin (5-hydroxytryptamine, 5-HT) is required for both very early non-neuronal developmental events, and in the CNS as a neurotransmitter to modulate behavior. 5-HT is synthesized, at least in part, by the actions of Drosophila tryptophan-phenylalanine hydroxylase (DTPH), a dual function enzyme that hydroxylates both phenylalanine and tryptophan. DTPH is expressed in numerous tissues as well as dopaminergic and serotonergic neurons, but it does not necessarily function as both enzymes in these tissues. Deficiencies in DTPH could affect the production of dopamine and serotonin, and thus dopaminergic and serotonergic signaling pathways. In this paper, we show that DTPH exhibits differential hydroxylase activity based solely on substrate. When DTPH uses phenylalanine as a substrate, regulatory control (end product inhibition, decreased PAH activity following phosphorylation, catecholamine inhibition) is observed that is not seen when the enzyme uses tryptophan as a substrate. These studies suggest that regulation of DTPH enzymatic activity occurs, at least in part, through the actions of its substrate.     

Evaluation of Production Parameters of Earthworms <Emphasis Type="Italic">Eiseniella tetraedra</Emphasis> Sav. in a Laboratory Culture

Use of earthworm Eiseniella tetraedra in vermiculture was tested for the first time. The structural parameters of its natural and laboratory populations under constant hydrothermal conditions were determined together with the production parameters such as the rate of weight gain, cocoon production, and duration of embryonic development. The mean weight gain was 84% of the baseline within 6 weeks, the rate of cocoon deposition was 0.8 per week, and the incubation duration was about 3 weeks, which provided for population doubling within 3 months. The obtained data demonstrated a good adaptation of Eiseniella tetraedra to the culture conditions with an artificial organic substrate.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 323–326.Original Russian Text Copyright © 2005 by Barne, Striganova.     

Mating behavior in the ant, <Emphasis Type="Italic">Myrmecina graminicola</Emphasis> (Myrmicinae)

Summary Sexual behavior of Myrmecina graminicola in laboratory conditions is described. Virgin females, both gynomorphs and intermorphs, exhibit an inconspicuous "sexual calling", apparently depositing a sex pheromone on the substrate close by. The sexual pheromone is produced in the poison gland. Copulation needs between 40 and 60 seconds, dealation of gynomorphs follows soon after. Some observations are in marked contrast to former reports, e.g. on duration of copulation in M. graminicola (Donisthorpe, 1927: several hours) and on the source of a sex pheromone in the closely related M. nipponica (Murakami et al., 2002: pygidial gland).Received 4 February 2003; revised 19 May 2003; accepted 19 May 2003.     

Pathogenicity of <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> (Deuteromycetes) and permethrin to <Emphasis Type="Italic">Ixodes scapularis</Emphasis> (Acari: Ixodidae) nymphs

Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC₅₀ of 10⁷ spores/ml and induced 70% mortality at 10⁹ spores/ml. In a field study, however, 10⁹ spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.     

Tail Autotomy Plays No Important Role in Influencing Locomotor Performance and Anti‐Predator Behavior in a Cursorial Gecko

We used the frog‐eyed sand gecko (Teratoscincus scincus) as a model system to evaluate the locomotor costs of tail loss, and to examine whether tailless geckos use alternative anti‐predator behavior to compensate for the costs of tail loss. Of the 16 field‐captured geckos, eight were used as experimental animals and the remaining ones as controls. Locomotor performance, activity level and anti‐predator behavior were measured for experimental geckos before and after the tail‐removing treatment. Control geckos never undergoing the tail‐removing manipulation were measured to serve as controls for the measurements taken at the same time for experimental geckos. Experimental geckos did not differ from controls in activity level before they underwent the tail‐removing manipulation, but became less active thereafter. The mean locomotor stamina of tailless geckos was reduced by about 30% of the mean value for tailed ones. However, as the maximum stamina predicted from the laboratory trials is seldom required in nature, we expect that the costs associated with the reduced locomotor stamina may be relatively minor in T. scincus. All other examined locomotor (overall speed, maximal speed and stride length) and behavioral (distance to refuge, approach distance and flight distance) traits were not affected by the tail‐removing manipulation. Overall, our results suggest that tail autotomy plays no important role in influencing locomotor performance and anti‐predator behavior in lizards where the tail has no direct role in locomotion but is used to direct predatory strikes away from the torso.     

Courtship behavior and discrimination between potential mates by maleDelia antiqua (Diptera: Anthomyiidae)

The repertoire of courtship behaviors of male onion maggots,Delia antiqua (Meigen), in a laboratory bioassay chamber, was analyzed by direct observation and by video recordings, in conjunction with a multichannel event recorder. Seven courtship behaviors were categorized: inspection from the substrate, aerial inspection, contact from the substrate, contact from the air, genital alignment, copulation, and male-male interaction. The frequency distribution of copulation bouts was best described by a Poisson distribution; peak mating activity occurred about 1 h into the bioassay. The duration in copulo, however, was extremely variable. On average, males spent 30 sin copulo (n=183); <30% of bouts were >50 s. The ability of males to discriminate between sexes, sexually immature and mature females, and between females ofD. antiqua and the cabbage maggot,Delia radicum (L.), was most pronounced in the elements of genital alignment and attempted copulation. The courtship and mating behavior inD. antiqua is consistent with a sequence that relies initially primarily on indiscriminate visual recognition of a potential mate, followed by species-and sex-specific semiochemical recognition upon contact.     

Cloning of a<Emphasis Type="Italic"> decapentaplegic</Emphasis> orthologue from the sawfly,<Emphasis Type="Italic"> Athalia rosae</Emphasis> (Hymenoptera), and its expression in the embryonic appendages

The cDNA of a decapentaplegic (dpp) orthologue from the sawfly, Athalia rosae (Hymenoptera), was cloned and characterized. The clone (Ar dpp) was 2,566 bp long and encoded 395 amino acids in a single open reading frame. Genomic Southern blotting showed that Ar dpp is a single copy gene. The deduced amino acid sequence can be aligned along its entire length with known insect DPPs. It shared common characteristics such as a signal sequence, a pro-domain region, and a ligand domain with seven cysteines at conserved locations. Ar dpp was expressed as a single 5.0-kb mRNA in embryos, larvae, pupae and adults. In situ hybridization showed that Ar dpp was expressed in the dorsal region proper in early embryonic stages and in the embryonic appendages of cephalic segments (labrum, antenna, mandible, maxilla, and labium), thoracic segments (thoracic legs), and all abdominal segments except the tenth segment (pleuropodia and proleg primordia). The present results indicate that Ar dpp expression reflects the primary determination of embryonic appendages.Edited by D. TautzThe sequence reported in this paper has been deposited in the DDBJ/EMBL/GenBank database with the accession number AB121072     

Environmental and Social Factors Associated with the Occurrence of Stone-Handling Behavior in a Captive Troop of <Emphasis Type="Italic">Macaca fuscata</Emphasis>

Stone-handling, a documented behavioral tradition in Japanese macaques (Macaca fuscata), occurs in both captive and provisioned free-ranging troops. We utilize data systematically collected as part of a broader investigation of stone-handling behavior in a captive troop to elucidate the environmental and social factors responsible for its occurrence. We analyzed contexts of stone-handling over 18 mo to determine under what conditions individuals most often perform it. There is clear seasonal variation in the occurrence of stone-handling. The lowest number and shortest duration of stone-handling bouts were in winter, gradually increasing to a peak in summer, and again decreasing toward autumn. Monkeys stone-handled more on clear sunny days than on cloudy or rainy ones. They displayed the behavior less under stressful conditions caused by human intervention or by aggression among troop members. Such stressful social conditions appeared to decrease individual motivation for stone-handling. In other words, individuals most frequently performed stone-handling under more relaxed environmental and social conditions. The findings are consistent with the hypothesis that stone-handling is a form of solitary object play behavior in macaques.     

Mandibular ontogeny in the miocene great apeDryopithecus

The type mandible of Dryopithecus fontani,Lartet 1856, has been discovered to be not fully adult. Its development corresponds in dental age to that of a 6-to 8-year-old chimpanzee. Because of its immaturity, a number of seemingly distinctive features of this mandible (some of which resemble hominids) would have been lost with full adulthood. Closed tooth rows, a recurved canine, and a vertical ascending mandibular ramus are related to the age of the specimen. They therefore do not foreshadow hominid characteristics. It is stressed that consideration of individual age is an important factor in interpreting the dentitions of fossil and extant hominoids.