Influence of Nematode Parasitism,Body Size,Temperature, and Diel Period on the Flight Capacity of <Emphasis Type="Italic">Sirex noctilio</Emphasis> F. (Hymenoptera: Siricidae)

Sirex noctilio F. (Hymenoptera: Siricidae) is a woodwasp of pine trees that has recently invaded and established in North American forests. Although S. noctilio has had a limited impact in North America to date, there is some concern that it could have a significant impact on pine plantations, especially in the southeastern U.S.A. Moreover, there are few data on the flight capacity of male S. noctilio. We found no association between parasitism by D. siricidicola and whether or not S. noctilio initiated flight on the flight mill. Male wasps that were parasitized by nematodes were heavier than non-parasitized males, but there was no significant difference in mass between parasitized and non-parasitized females. We also examined the flight capacity of male and female S. noctilio in relation to nematode parasitism, body mass, temperature (for only males), and diel period. Body mass, temperature, and diel period affected flight in S. noctilio such that wasps were generally observed to fly faster, farther, and more frequently if they were heavier, flying at warmer temperatures, and flying during the photoperiod. The fact that nematode-parasitized male wasps were found to fly farther than the non-parasitized males is consistent with the hypothesis that nematode parasitism does not negatively affect the flight capacity of S. noctilio.     

Effects of male apparent length on female preference for absolute body size in <Emphasis Type="Italic">Xiphophorus helleri</Emphasis>

Female green swordtails (Xiphophorus helleri) prefer males of longer body and sword lengths, which may reflect perceptual constraints. Larger males project a larger image onto the female’s retina at a given viewing distance, which may elicit greater stimulation of the visual system and a stronger behavioral response. This study investigates the effects of male apparent size, as affected by proximity and sword length, on female preference for absolute body size in X. helleri. Females were presented pairs of dummy males in ten treatments organized into six categories: (1) the Actual Length Control where identically sized males were held at different viewing distances from the female; (2) the Sword Compensation Treatment in which viewing distance and apparent length (body + sword) were held constant, pairing sworded with swordless dummies of equal total length; (3) the Body Length Preference Treatment where male distance from the female was held constant, while varying body size; (4) the Apparent (Sword) Length Preference Treatments where male distance from the female was held constant, while varying sword length; (5) the Apparent Length Controls where body length, sword length, and viewing distances varied while holding apparent length constant; and (6) the Experimental Treatment in which the smaller-sworded male of the pair appeared larger. In each of the Actual Length Control, Body, and Sword Length Treatments, females preferred the closer, larger-bodied, and longer-sworded males, respectively. However, females exhibited preferences in neither any of the Apparent Size Control treatments nor any of the Sword Compensation Treatment. Additionally, females in the Experimental Treatment preferred the apparently longer-sworded dummy to the male whose sword was actually longer. These results suggest that female preference for male body and sword length is based on the male’s apparent rather than actual size.     

Complex adaptive traits between mating behaviour and post-copulatory sperm behaviour in squids

Emergence of male dimorphism within a species is the evolutionary process of disruptive selection. In squids, two types of male mating behaviour, known as alternative reproductive tactics (ARTs), are causally associated with adult body size. Males inseminate promiscuously with the same females; large “consort” males internally, and small “sneaker” males externally. Previously we found that in Heterololigo bleekeri, sneaker (but not consort) spermatozoa are able to swarm by sensing self-emitted CO₂. This suggests that a swarming trait might have arisen in sneakers as a “sperm cooperation” strategy among sibling sperm in order to compete with consort males, or as a consequence of adaptation to external fertilization. To address these possibilities, we examined six species where three patterns of insemination are present, namely, only internal, only external, or both ARTs. In three species that employ both ARTs (H. bleekeri, Loligo reynaudii and Uroteuthis edulis), sneaker spermatozoa always exhibited self-swarming capacity. In Idiosepius paradoxus and Todarodes pacificus, which use only external insemination, spermatozoa formed a swarm. However, in Euprymna morsei, which use only internal insemination, sperm were unable to swarm. These results suggest that the self-swarming trait is likely to be linked to the mode of insemination rather than the alternative strategy used by sneaker males. Thus we propose a new hypothesis in which cooperative sperm behaviour has evolved not only through kin selection against sperm competition risks, but also through adaptation to the insemination/fertilization environment.     

Sources contribution for benthic invertebrates: an inter-lake comparison in a flood plain system

Dwarfism in males is a common phenomenon in planktonic monogonont rotifers. Considering the small body size of males, some studies suggested that the development time of male rotifers is faster than that of females. However, empirical studies associated with such a speculation are scarce. In this study, we used two common rotifer species, Brachionus calyciflorus and Brachionus plicatilis (each with two geographical populations), to test the hypothesis that the development time of dwarf males is significantly shorter than that of females. Results showed that male eggs (embryos) were deposited much faster than female eggs (embryos) in both Brachionus species. However, the embryonic development time of these small male eggs (embryos) was longer than that of large female eggs (embryos). As a result, males needed significantly longer total development time than females. The total development time of males was 2–3 h longer than that of females in both Brachionus species. Male-producing and female-producing females in the two Brachionus species did not show any difference in development time. Because sexual reproduction begins at high population densities in both species, postponement of development in males will be advantageous by decreasing mating costs in male rotifers.     

Intra-specific variation of sperm length in the malaria vector <Emphasis Type="Italic">Anopheles gambiae</Emphasis>: males with shorter sperm have higher reproductive success

Background

Intra-specific variation in sperm length influences male reproductive success in several species of insects. In males of the malaria vector Anopheles gambiae, sperm length is highly variable but the significance of this variation is unknown. Understanding what determines the reproductive success of male mosquitoes is critical for controlling malaria, and in particular for replacing natural populations with transgenic, malaria-resistant mosquitoes.

Methods

A laboratory population of A. gambiae males was tested for intra-specific variation in sperm length. A full-sib quantitative genetic design was used to test for a genetic component of sperm length in A. gambiae males and estimate its heritability. This study also tested for a relationship between sperm length and male reproductive success in A. gambiae. Male reproductive success was measured as the proportions of inseminated and ovipositing females.

Results

There was intra-specific variation of sperm length in A. gambiae. There was no significant genetic variation in sperm length and its heritability was low (h² = 0.18) compared to other insects. Sperm length was correlated with male body size (measured as wing length). Males with short sperm had significantly higher reproductive success than males with long sperm and this was independent of body size.

Conclusion

This is the first study to demonstrate intra-specific variation in sperm length in A. gambiae and that males with short sperm have higher reproductive success. That sperm length influences female oviposition is important for any strategy considering the release of transgenic males.

     

Potential Reproductive Advantage of Short-over Long-Winged Adult Males of the Cricket <Emphasis Type="Italic">Velarifictorus ornatus</Emphasis>

A trade-off between flight capability and reproduction is well known in adult females of the wing-dimorphic cricket Velarifictorus ornatus, but it is not clear whether such a trade-off exists in adult males of the species. In the present study, we investigated sexual maturation time, mating frequency, and the fertilization success of spermatophores after sequential mating in long-winged (LW) and short-winged (SW) adult males of V. ornatus to evaluate the potential reproductive advantage of the SW over the LW male morph. We found that the SW males of V. ornatus attained sexual maturity earlier and produced heavier spermatophores during the early stage after adult emergence than their LW counterparts. Additionally, within a 24-h mating period, the SW males showed a higher mating frequency, greater spermatophore weight, and shorter intermating time interval compared with their LW counterparts. Although females copulated with the two male morphs produced eggs of similar size, fertilization success by SW males was significantly higher than by the LW males. These results provide support for a trade-off between dispersal capability and reproduction success in wing-dimorphic males of V. ornatus.     

Male-male interactions and their influence on the mating behavior and success in the fountain darter, <Emphasis Type="Italic">Etheostoma fonticola</Emphasis>

Behavioral interactions between individuals of the same sex can affect the outcome of intersexual selection. For this reason, intrasexual selection is oftentimes examined independently from intersexual selection in studies aimed at understanding mating behaviors. However, a more complete understanding of sexual selection effects within a population can only come from exploring both intrasexual and intersexual selection and the potential interactions between the levels of selection. Association preferences in male and female Etheostoma fonticola do not reveal a size preference for same sex or opposite-sex individuals. However, male-male interactions may influence female choice in E. fonticola. We examined whether male E. fonticola that differ in body size exhibit differences in agonistic behaviors and mating success. Larger males do exhibit higher rates of aggressive behaviors and smaller males, in turn, exhibit more defensive behaviors. However, differences between larger and smaller males in male-male interactions did not translate into differences in spawning success. These results suggest that male size influences dominance relationships in E. fonticola but not mating success. There were also no differences between large and small males in mating attempts, which could be an outcome of the year-round breeding season found in this species, females laying eggs singly, or males fertilizing eggs individually.     

New scarab-beetle species (Coleoptera,Scarabaeidae, Aphodiinae,Orphninae) from Central Asia and Southern Africa

Three new scarab-beetle species are described. Aphodius moronensis sp. n. (northern Mongolia) and A. kozlovi sp. n (eastern Tibet) with modified spurs on fore tibiae in males are placed in the falcispinis group of the subgenus Agolius but are similar to the grafi group of the subgenus Chilothorax in the shape of parameres and elytral pattern. The new species differ from A. falcispinis in the shape of the spur; A. moronensis sp. n. also differs in the shape of the body and parameres. Orphnus transvaalensis sp. n. is the second apterous Orphnus species found in Southern Africa. It differs from the closely related O. harrisoni in the shape of parameres, position of the hornlike clypeal process, and in a smaller body size.     

Infestation with the parasitic nematode <Emphasis Type="Italic">Philometra ovata</Emphasis> does not impair behavioral sexual competitiveness or odor attractiveness of the male European minnow (<Emphasis Type="Italic">Phoxinus phoxinus</Emphasis>)

Our understanding on the role of chemical signals in parasite-mediated sexual selection is still limited, and only some existing studies have focused on fish. Furthermore, published studies on the effect of parasite infection on behavioral sexual competition of the male hosts have yielded contradictory results. Here, we examined whether the infection of the body cavity-dwelling parasitic nematode Philometra ovata influences odor-based female choice and behavioral sexual competition (dominance and courtship behavior) between males in the European minnow (Phoxinus phoxinus), the cyprinid fish host. In contrast to our predictions, we found that naïve females showed no preference between the odors of infected and non-infected males, thus indicating that P. ovata infection may not affect odor-based female choice. Moreover, P. ovata did not impair sexual competitiveness of their hosts either. Our results indicate that despite its relatively large size, P. ovata may not alter sexual cues and the success of the male hosts in sexual selection.     

Factors influencing the dispersal of a native parasitoid, <Emphasis Type="Italic">Phasgonophora sulcata</Emphasis>, attacking the emerald ash borer: implications for biological control

High parasitism by a native parasitoid, Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae), has been reported on emerald ash borer (hereafter EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in North America. Use of this parasitoid in an augmentative biological control program has been proposed to slow the spread of EAB, yet information is lacking on key aspects of this parasitoid’s dispersal. We document the flight capacity and walking activity of P. sulcata, its potential fecundity, and describe how age, body size, temperature, and time of day affect these parameters. Wasp flight capacity, measured using flight mills, increased with temperature and decreased with age. Unexpectedly, age and body size did not affect wasp walking activity, and we saw no relationship between walking activity and flight capacity. Older wasps had lower potential fecundity than younger wasps. These results suggest that P. sulcata should be released as pupae near EAB-infested ash trees to improve efficacy and potential biological control success.     

Population estimate and body size of European pond turtles (<Emphasis Type="Italic">Emys orbicularis</Emphasis>) from Pazarağaç (Afyonkarahisar/Turkey)

Data on population size, adult sex ratio, body size and mass are provided for a population of the turtle Emys orbicularis near Pazara?aç (Afyonkarahisar/Turkey). Using the mark-recapture method (triple catch), a population size of 664 turtles was estimated (95% confidence interval, range 332–996), corresponding to a density of 83 turtles per hectare (range 41.5–124.5). The adult sex-ratio was significantly skewed in favor of males (2.02 males: 1 female; P < 0.001). Almost all recorded specimens were adult (98.1%). Mean straight carapace length (SCL) and body mass (BM) of adult turtles were: SCL = 128.65 mm, BM = 345 g for males (n = 168) and SCL = 135.37 mm, BM = 463 g for females (n = 83).     

New species of the bristletail families Ateluridae and Lepismatidae (Zygentoma) from Abkhazia and Adygea

Four new species of the bristletail families Ateluridae (Atelura abkhazica sp. n. and Nipponatelurina caucasica sp. n.) and Lepismatidae (Lepisma xylophila sp. n. and L. adygei sp. n.) are described. Atelura abkhazica sp. n. differs from the other species of the genus Atelura in a smaller size, smaller number of ovipositor divisions, in the presence of apical sensory cones on the male parameres, which are absent in the other species of the genus, and in a fewer number of lateral pegs on urotergite X. The genus Nipponatelurina comprises two species (N. kurosai Mendes et Machida, 1994 and N. caucasica sp. n.). The distinguishing features of N. caucasica sp. n. include a significant number of short minute thin cilia on the head capsule, a longer ultimate segment of the maxillary palp, and a fewer number of setae at the posterior margin of urosternites IV–VII. Lepisma xylophila sp. n. differs from L. saccharinum and L. chlorosoma in the distribution of epidermic pigment and in the urotergites chaetom. Lepisma adygei sp. n. is most closely related to the synanthropic species L. saccharinum, but differs in the size of the body, color of scales on the upper surface of the body, and in the structure of the labial palps, urotergite X, ovipositor, and parameres.     

New species of the bristletail genus <Emphasis Type="Italic">Allopsontus</Emphasis> Silv. (Microcoryphia,Machilidae) from Southeastern Kazakhstan and Abkhazia

Two new bristletail species, Allopsontus (Anisoptinus) nigrus sp. n. from Southeastern Kazakhstan and A. (Kaplinilis) abkhazicus sp. n. from Abkhazia, are described. A. nigrus sp. n. differs from the only other known species of the subgenus Anisoptinus, A. borgustani Kaplin 2015, in a number of characters, namely, in more rounded paired ocelli, an extended apical segment of the labial palpus, a long articulated ovipositor, and in the absence of short appressed pigmented setulae on the maxillary and labial palpi in males. A. abkhazicus sp. n. can be easily distinguished from all the other known species of the subgenus Kaplinilis by the absence of short appressed pigmented setulae on the maxillary and labial palpi in the males, the absence of a projection with numerous spiniform setae on the male fore femur, and in shorter male genital appendages. The ocellus of the male and female is 2.8-2.9 times as wide as long; the length to width ratio of the eye is 0.9-1.0; the ovipositor consists of 60 divisions.     

Homologous gene targeting of a carotenoids biosynthetic gene in <Emphasis Type="Italic">Rhodosporidium toruloides</Emphasis> by <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation

Objectives

To target a carotenoid biosynthetic gene in the oleaginous yeast Rhodosporidium toruloides by using the Agrobacterium-mediated transformation (AMT) method.

Results

The RHTO_04602 locus of R. toruloides NP11, previously assigned to code the carotenoid biosynthetic gene CRTI, was amplified from genomic DNA and cloned into the binary plasmid pZPK-mcs, resulting in pZPK-CRT. A HYG-expression cassette was inserted into the CRTI sequence of pZPK-CRT by utilizing the restriction-free clone strategy. The resulted plasmid was used to transform R. toruloides cells according to the AMT method, leading to a few white transformants. Sequencing analysis of those transformants confirmed homologous recombination and insertional inactivation of CRTI. When the white variants were transformed with a CRTI-expression cassette, cells became red and produced carotenoids as did the wild-type strain NP11.

Conclusions

Successful homologous targeting of the CrtI locus confirmed the function of RHTO_04602 in carotenoids biosynthesis in R. toruloides. It provided valuable information for metabolic engineering of this non-model yeast species.

     

Dynamic associations between <Emphasis Type="Italic">Ips sexdentatus</Emphasis> (Coleoptera: Scolytinae) and its phoretic mites in a <Emphasis Type="Italic">Pinus pinaster</Emphasis> forest in northwest Spain

The relationship between the pine bark beetle Ips sexdentatus and its phoretic mites in a Pinus pinaster forest in northwest Spain was studied during 2014. Four species of mites were collected, three of them from the body of the beetle—Histiostoma ovalis, Dendrolaelaps quadrisetus and Trichouropoda polytricha—the fourth, Cercoleipus coelonotus, was collected from the sediments. The main aims of this study were to explore (1) mite diversity and related parameters, (2) the location on the body of the (male and female) beetle, as well as mite assemblages, and (3) the seasonal dynamic association between mite species and the beetle. Results indicated that the diversity oscillated around 0.71 through the study period and the most dominant, frequent and abundant mite was H. ovalis. Histiostoma ovalis was found attached to almost all parts of the body (mainly on the elytral declivity and ventral thorax), whereas D. quadrisetus was exclusively found under the elytra, and T. polytricha displayed affinity towards the elytral declivity as well as the ventral thorax. None of the mite species displayed any preference for the sex of the beetle and the most frequent mite assemblage was H. ovalis, T. polytricha and D. quadrisetus all together. Maximum abundance of each phoretic mite species was related with each of the flight peaks of the beetle that would indicate that these mite species use phoresy as a primary method of transport for colonizing new food sources.     

Antipredator Behavioral Traits of some <Emphasis Type="Italic">Agriotes</Emphasis> Wireworms (Coleoptera: Elateridae) and their Potential Implications for Species Identification

Many insects show a typical antipredator behavior. The two simplest tactics are immobilization and flight. The antipredator behavior of wireworms, the soil-dwelling polyphagous larvae of click beetles, has not yet been investigated. Birds are known to attack wireworms. Our experimental method (picking up and dropping wireworms) mimics the first attack of a predator, such as a bird. In Europe, some Agriotes species are of particular importance as crop pests. As these species differ considerably, in ecology, damage threshold, and pathogen resistance, knowing more about the species specific biology and behavior will support the establishment of successful control measures. In an extensive microcosm study, we observed the antipredator behavior of wireworms belonging to four different Agriotes species (A. lineatus, A. obscurus, A. sordidus, and A. ustulatus) before and during digging into the soil after a startle-stimulus. We recorded wireworm immobility frequency and duration, and locomotor activity at three temperatures. We also analyzed genetic and morphologic attributes of A. lineatus larvae from two different origins. Following behavior types were found reflecting different escape tactics: (a) distinct tonic immobility (A. lineatus), (b) brief/inconsistent tonic immobility (A. obscurus, A. sordidus), and (c) immediate fleeing/burying (A. ustulatus). Additionally, we found small but significant differences in morphology, behavior, and genetics (PCR results) between A. lineatus larvae originating from the Netherlands and those originating from Germany. The biological information we gathered about each species will further increase the understanding of these insects and improve interpretation of future experimental data. In addition, the described behavioral differences between Agriotes obscurus and A. lineatus wireworms may represent a useful additional criterion in morphological species identification.     

Anti-Müllerian hormone may regulate the number of calbindin-positive neurons in the sexually dimorphic nucleus of the preoptic area of male mice

Background

The male brain is putatively organised early in development by testosterone, with the sexually dimorphic nucleus of the medial preoptic area (SDN) a main exemplifier of this. However, pubescent neurogenesis occurs in the rat SDN, and the immature testes secrete anti-Müllerian hormone (AMH) as well as testosterone. We have therefore re-examined the development of the murine SDN to determine whether it is influenced by AMH and/or whether the number of calbindin-positive (calbindin^+ve) neurons in it changes after pre-pubescent development.

Methods

In mice, the SDN nucleus is defined by calbindin^+ve neurons (CALB-SDN). The number and size of the neurons in the CALB-SDN of male and female AMH null mutant (Amh ^-/- ) mice and their wild-type littermates (Amh ^+/+ ) were studied using stereological techniques. Groups of mice were examined immediately before the onset of puberty (20 days postnatal) and at adulthood (129–147 days old).

Results

The wild-type pre-pubertal male mice had 47% more calbindin^+ve neurons in the CALB-SDN than their female wild-type littermates. This sex difference was entirely absent in Amh ^-/- mice. In adults, the extent of sexual dimorphism almost doubled due to a net reduction in the number and size of calbindin^+ve neurons in females and a net increase in neuron number in males. These changes occurred to a similar extent in the Amh ^-/- and Amh ^+/+ mice. Consequently, the number of calbindin^+ve neurons in Amh ^-/- adult male mice was intermediate between Amh ^+/+ males and Amh ^+/+ females. The sex difference in the size of the neurons was predominantly generated by a female-specific atrophy after 20 days, independent of AMH.

Conclusions

The establishment of dimorphic cell number in the CALB-SDN of mice is biphasic, with each phase being subject to different regulation. The second phase of dimorphism is not dependent on the first phase having occurred as it was present in the Amh ^-/- male mice that have female-like numbers of calbindin^+ve neurons at 20 days. These observations extend emerging evidence that the organisation of highly dimorphic neuronal networks changes during puberty or afterwards. They also raise the possibility that cellular events attributed to the imprinting effects of testosterone are mediated by AMH.