Flash signal evolution in Photinus fireflies: Character displacement and signal exploitation in a visual communication system

Animal communication is an intriguing topic in evolutionary biology. In this comprehensive study of visual signal evolution, we used a phylogenetic approach to study the evolution of the flash communication system of North American fireflies. The North American firefly genus Photinus contains 35 described species with simple ON–OFF visual signals, and information on habitat types, sympatric congeners, and predators. This makes them an ideal study system to test hypotheses on the evolution of male and female visual signal traits. Our analysis of 34 Photinus species suggests two temporal pattern generators: one for flash duration and one for flash intervals. Reproductive character displacement was a main factor for signal divergence in male flash duration among sympatric Photinus species. Male flash pattern intervals (i.e., the duration of the dark periods between signals) were positively correlated with the number of sympatric Photuris fireflies, which include predators of Photinus. Females of different Photinus species differ in their response preferences to male traits. As in other communication systems, firefly male sexual signals seem to be a compromise between optimizing mating success (sexual selection) and minimizing predation risk (natural selection). An integrative model for Photinus signal evolution is proposed.     

Assessing Condition-dependence of Male Flash Signals in <Emphasis Type="Italic">Photinus</Emphasis> Fireflies

Females often show a preference for exaggerated male sexual traits or courtship behaviors. Such preferences can benefit females if trait expression is correlated with male genetic quality or phenotypic condition. Previous studies of several Photinus fireflies have revealed considerable intraspecific variation in the bioluminescent courtship signals emitted by males, and have also demonstrated that females prefer more conspicuous male signals. Thus, females might gain information about male phenotypic quality if courtship signals reflect male condition. We examined possible condition-dependence of Photinus male courtship signals using two complementary approaches. First we experimentally manipulated male mating status, which is expected to affect male condition by depleting resources required for nuptial gift formation, and looked at how individual male flash signals changed with mating status and over time. We used an additional approach to assess condition-dependence by examining whether a relationship exists between flash signal parameters and measures of male condition and body shape. We found that the pulse rate of P. greeni courtship signals was not altered by male mating status or age, and that the pulse duration of P. ignitus signals was also not affected by male mating status. In P. pyralis fireflies, males showed a non-significant trend toward reduced signal pulse duration with age. When we examined the relationship between male flash signals and condition measures, we found no effect of male condition or body shape on courtship signals in P. greeni or P. ignitus; in P. pyralis, males with wider body shapes produced longer duration flash signals. On the other hand, we found no evidence in P. pyralis that condition predicted flash duration. Taken together, these results indicate that Photinus males’ flash signals do not reflect adult male condition, and suggest that females are unlikely to use courtship signals as an indicator of male phenotypic quality.     

Intraspecific interactions of Argyrodes antipodiana,a kleptoparasitic spider from New Zealand

Abstract

Intraspecific interactions (male‐male, female‐female, male‐female) of Argyrodes antipodiana (O.P.‐Cambridge), a New Zealand kleptoparasitic spider, were studied in the laboratory. Interactions, especially male‐female interactions, tended to be complex and of long duration, and included 32 different displays being used in sequences that could last for over 5 h. In male‐female interactions, there were numerous alternations between displaying and copulating, but most courtship followed the initial copulation. The possible adaptive significance of A. antipodiana's complex courtship is discussed. The role of pheromones in the intraspecific interactions of this species is also investigated.     

MATING CALLS OF THE IBERIAN MIDWIFE TOADS ALYTES OBSTETRIC ANS BOSCAI AND ALYTES CISTERNASII

ABSTRACT

The mating calls of the Iberian midwife toads, A.o. boscai and A. cisternasii show clear differences. The calls of A.o. boscai have a shorter duration (104.8ms) and a lower fundamental frequency (1.33 kHz) than those of A. cisternasii (172.0 ms and 1.45 kHz), between 12° and 16°C. In both species signal duration was found to be influenced by temperature.     

ADVERTISEMENT CALLS OF THE TREE FROGS,HYLA ARBOREA AND HYLA SAVIGNYI (ANURA: HYLIDAE) IN TURKEY

ABSTRACT

The systematic classification of tree frogs (Hyla) inhabiting different regions of the country of Turkey is unclear. Recordings of natural advertisement calls of individual male tree frogs in different locations in Turkey were analyzed to determine variation in acoustic features that may be related to taxonomic status. Multivariate analysis of covariance showed that call duration, intercali interval and number of pulses per call varied significantly between frogs in different locales. Call duration, intercall interval, and number of pulses per call were related to air temperature. Dominant frequency differed significantly between different groups of frogs, and was temperature-independent. These data are consistent with the hypothesis that tree frogs in Turkey represent two distinct species, Hyla arborea and Hyla savignyi.     

江山乌猪肠道黏膜菌群组成及其功能的性别差异

肠道黏膜微生物在调控宿主生理功能方面发挥重要作用,其结构组成受到多种因素影响。性别被认为是塑造肠道微生物的因素之一。然而,性别对肠道黏膜菌群的差异影响还不清楚。【目的】以江山乌猪为研究对象,探究性别差异对其肠道黏膜微生物组成及功能的影响。【方法】选取性成熟的雌性和雄性江山乌猪各8头,利用16S rRNA基因高通量测序技术分析回肠和结肠黏膜菌群。【结果】在回肠黏膜中,雄性江山乌猪菌群的Chao1指数和Shannon指数显著高于雌性(P<0.05),在结肠黏膜中,不同性别江山乌猪菌群Chao1指数和Shannon指数无显著差异(P>0.05)。菌群差异分析显示,回肠黏膜中,沙雷氏菌属(Serratia)和埃希氏志贺菌属(Escherichia_Shigella)在雌性组中的相对丰度显著高于雄性组(P<0.05),雄性组中Oscillospiraceae UCG-005、拟普雷沃氏菌属(Alloprevotella)、布劳特氏菌属(Blautia)和Prevotellaceae_NK3B31_group相对丰度显著高于雌性组(P<0.05);结肠黏膜中,雌性组中unclassified_Muribaculaceae、Rikenellaceae_RC9_gut_group和Prevotellaceae UCG-003相对丰度显著高于雄性组(P<0.05),Oscillospiraceae UCG-005、Lachnospiraceae_NK4A136_group和unclassified_Lachnospiraceae在雄性组中相对丰度更高(P<0.05)。功能预测发现,雄性乌猪回肠黏膜菌群显著富集了氨基酸代谢、碳水化合物代谢和能量代谢等功能途径(P<0.05);结肠黏膜菌群主要富集了膜转运相关的ABC转运蛋白和信号转导相关的双组分系统等功能途径(P<0.05)。【结论】不同性别江山乌猪肠黏膜菌群结构及功能具有明显差异。这些结果揭示了不同性别江山乌猪肠道黏膜菌群的差异特征,为了解和挖掘我国地方畜禽品种肠道微生物资源提供部分参考。     

First record of male drumming call of the genus Capnioneura Ris, 1905 (Plecoptera,Capniidae)

The male call of Capnioneura mitis, produced by drumming, is recorded and analyzed for the first time. It also represents the first known signal for the genus. It consists of a highly variable number of beats (2–32) with inter‐beat duration approximately constant along the call, but inter‐beat duration is temperature dependent. Thus, at 13°C the mean inter‐beat duration is 1.397 s (SD = 0.050) while at 21°C it is 1.139 s (SD = 0.093). The call pattern exhibited by this species, as those of the majority of previously studied Capniidae species, can be catalogued as an ancestral or near‐ancestral percussive monophasic signal.     

The Effect of Male Competition on the Courtship Song of Drosophila melanogaster

The courtship song of Drosophila has been extensively used as a model system for studies of sexual selection and species recognition. Traditionally, the courtship song has been recorded from males placed individually with a female. However, under natural conditions females are exposed to multiple courting males, and the effect of their joint signal on mate recognition by the female is not yet understood. Here, we recorded the courtship behavior of D. melanogaster males singing either individually to a female lpar;1:1) or in the presence of an additional male lpar;2:1). We compared the structure of the male song in the two experimental designs. Our results show that when two males courted a female their songs could overlap each other. Males produced a significantly different signal in the presence of competition; the duration of each song component was significantly shorter and the rate of singing was markedly lower. The present study demonstrates that male competition can dramatically alter the acoustic signal detected by the female.     

碱性蛋白酶SubC在枯草芽孢杆菌中的高效异源表达

【背景】碱性蛋白酶是工业用酶中占比最大的酶类,广泛应用于清洁、食品、医疗等行业。近期研究发现碱性蛋白酶在生产生物活性肽方面有巨大潜力,这将进一步拓宽其在保健食品领域中的应用。【目的】利用枯草芽孢杆菌异源表达地衣芽孢杆菌来源的碱性蛋白酶SubC。【方法】通过筛选3种枯草芽孢杆菌宿主菌株(Bacillus subtilis 1A751、MA07、MA08)和6种信号肽(AmyE、AprE、NprE、Pel、YddT、YoqM),同时优化诱导剂浓度、发酵培养基和发酵时长,最终得到最优重组菌株MA08-AmyE-subCopt。【结果】重组菌株MA08-AmyE-subCopt的胞外酶活力为3.33×103 AU/mL,胞外蛋白分泌量为胞内可溶蛋白表达量的4倍,与携带野生型信号肽的对照组菌株WT相比,酶活提高了73.4%。【结论】异源碱性蛋白酶SubC在枯草芽孢杆菌中成功表达,为碱性蛋白酶SubC的表达和在保健食品领域的工业化应用提供了理论基础。     

Athletes underestimate sleep quantity during daytime nap opportunities

ABSTRACT

This study examined the difference between athletes’ self-reported and objective sleep durations during two nap opportunities. Twelve well-trained male soccer players’ sleep durations were assessed using polysomnography and a self-report question during a 60- and 120-min nap opportunity. Participants underestimated sleep compared to objective sleep assessments for both the 60-min nap opportunity (p = 0.004) and 120-min nap opportunity (p = 0.001). Soccer players underestimated their sleep duration by approximately 10 min per hour of nap opportunity. It is yet to be determined if athletes are likely to underestimate sleep duration during their main nighttime sleep period.     

Bioacoustic variation in Wren Troglodytes troglodytes populations on Welsh islands

ABSTRACT

Capsule: Duration and peak frequency of Wren Troglodytes troglodytes songs differ between Welsh islands (Skokholm, Flat Holm, and Sully Island) and a mainland site, suggesting random or cultural divergence.

Aims: The study tests for differences in bioacoustic traits in Wren song between four breeding sites.

Methods: Songs from breeding male Wrens were recorded from three Welsh islands and a representative location on the local mainland. Each sonogram was measured for six variables from the whole song and two distinct phrases from the beginning and middle. The variables were measured manually using an open source acoustic tool and compared between sites using generalized linear mixed-effects models.

Results: There was significant variation in song variables between island sites and the mainland. Skokholm Wren songs were significantly longer in duration than all other sites by up to 66%. Peak frequency was significantly different across all sites with Sully Island having the highest peak frequency and Skokholm the lowest.

Conclusion: The differences in song duration and frequency do not directly suggest a trend associated with selective pressures such as habitat or noise, but instead may be explained by non-selective drivers such as cultural drift or local dialect formation.     

Arbuscular mycorrhiza and water and nutrient supply differently impact seedling performance of dry woodland species with different acquisition strategies

Background: We recently demonstrated that dwarf male plants are much more common among mosses than hitherto thought. Dwarf plants, producing functional male sexual organs occur in 10–20% of the moss species worldwide.

Aims: We investigated how an inadvertent omission of dwarf males affects estimates of male sex expression rates and sex ratios.

Methods: We recorded frequencies of specimens with female-expressing plants, male-expressing normal-sized and/or dwarf plants, and sporophytes in herbarium material of five model species from Macaronesia. We analysed how frequency estimates of male occurrence and sex ratios were affected by excluding dwarf males.

Results: Occurrence of dwarf males was positively associated with sporophyte formation. When dwarf males were excluded, male mate availability was missed in 51–61% of specimens (in 74–76% of sporophyte-containing specimens). Specimen-level sex ratio was balanced in material with sporophytes in the three species exhibiting male dwarfism, but strongly female biased if dwarf males were omitted.

Conclusions: We provide the first quantitative evidence that sex-expressing dwarf males are essential for sexual reproduction and sporophyte production in mosses that form such males. Considering its abundance, male dwarfism therefore deserves more attention among plant biologists. Innovative approaches are required to further study the minute male plants.     

Body mass index related electrocardiographic findings in healthy young individuals with a normal body mass index

Introduction

An increased body mass index (BMI) (>25 kg/m²) is associated with a wide range of electrocardiographic changes. However, the association between electrocardiographic changes and BMI in healthy young individuals with a normal BMI (18.5–25 kg/m²) is unknown. The aim of this study was to evaluate the association between BMI and electrocardiographic parameters.

Methods

Data from 1,290 volunteers aged 18 to 30 years collected at our centre were analysed. Only subjects considered healthy by a physician after review of collected data with a normal BMI and in sinus rhythm were included in the analysis. Subjects with a normal BMI (18.5–25 kg/m²) were divided into BMI quartiles analysis and a backward multivariate regression analysis with a normal BMI as a continuous variable was performed.

Results

Mean age was 22.7 ± 3.0 years, mean BMI was 22.0, and 73.4% were male. There were significant differences between the BMI quartiles in terms of maximum P-wave duration, P-wave balance, total P-wave area in lead V1, PR-interval duration, and heart axis. In the multivariate model maximum P-wave duration (standardised coefficient (SC) = +0.112, P < 0.001), P-wave balance in lead V1 (SC = +0.072, P < 0.001), heart axis (SC = −0.164, P < 0.001), and Sokolow-Lyon voltage (SC = −0.097, P < 0.001) were independently associated with BMI.

Conclusion

Increased BMI was related with discrete electrocardiographic alterations including an increased P-wave duration, increased P-wave balance, a leftward shift of the heart axis, and decreased Sokolow-Lyon voltage on a standard twelve lead electrocardiogram in healthy young individuals with a normal BMI.

     

Exact Bayesian bin classification: a fast alternative to Bayesian classification and its application to neural response analysis

We investigate the general problem of signal classification and, in particular, that of assigning stimulus labels to neural spike trains recorded from single cortical neurons. Finding efficient ways of classifying neural responses is especially important in experiments involving rapid presentation of stimuli. We introduce a fast, exact alternative to Bayesian classification. Instead of estimating the class-conditional densities p(x|y) (where x is a scalar function of the feature[s], y the class label) and converting them to P(y|x) via Bayes’ theorem, this probability is evaluated directly and without the need for approximations. This is achieved by integrating over all possible binnings of x with an upper limit on the number of bins. Computational time is quadratic in both the number of observed data points and the number of bins. The algorithm also allows for the computation of feedback signals, which can be used as input to subsequent stages of inference, e.g. neural network training. Responses of single neurons from high-level visual cortex (area STSa) to rapid sequences of complex visual stimuli are analysed. Information latency and response duration increase nonlinearly with presentation duration, suggesting that neural processing speeds adapt to presentation speeds. Action Editor: Alexander Borst     

Review of subgenus Compsochromia Kiriakoff 1953 (Lepidoptera: Erebidae: Arctiinae,genus Balacra) with identification keys and description of a new species from Cameroon

Summary. Subgenus Compsochromia Kiriakoff 1953 is briefly reviewed. An overview of the taxonomic history of the group is provided along with a checklist covering all synonyms. Balacra flava n. sp. is described on the basis of eight specimens of both sexes collected in Cameroon. Three separate keys, based on male and female habitus as well as on the male genitalia, are presented for the determination of Compsochromia specimens. The vesica of B. compsa is described and illustrated for the first time.     

DURATION DISCRIMINATION IN NORTHERN BOBWHITE QUAIL

ABSTRACT

We examined the ability of northern bobwhite quail Colinus virginianus to discriminate along the duration dimension because of its suspected importance in their ability to identify individual covey members. If quail are using variability along this dimension to identify individuals we would expect their auditory resolving powers to be sufficiently refined in that dimension to make appropriate discriminations. Three 2-year old male bobwhite quail were trained using a positive reinforcement technique to discriminate between a 1000 Hz standard (correct) tone 600 ms in duration (100 ms rise/fall time) and a 1000 Hz comparison tone 300 ms in duration (also 10 ms rise/fall time). Quail were then required to discriminate between pairs of tones in which the duration of the comparison tone was progressively increased from 400 ms to 590 ms. Because of the categorical nature of the analysis we concluded that the two tones must differ in duration by 20 ms or more if they are to be discriminated correctly. Our study has shown that bobwhites are able to detect a 3% difference in duration around a standard tone 600 ms in duration, which compares favourably with results obtained from earlier studies with parakeets Melopsittacus undulatus and pigeons Columbia livia. Such a finely tuned duration discrimination ability also suggests that it is possible bobwhites may be using individual variability along the duration dimension of the separation call to identify individual covey members.     

Female Reproductive Cycle and Sexual Conflict over Precopulatory Mate-guarding in Thermosphaeroma (Crustacea, Isopoda)

In species with time-limited opportunities for insemination, precopulatory mate-guarding is expected to coevolve with the duration of female reproductive cycles. Despite this adaptation to female characteristics, it may also be advantageous for males to adjust the duration of guarding with respect to sex ratio because the benefits of guarding are dependent on the availability of females. If female fitness is reduced because of guarding, male guarding behavior leads to intersexual conflict. We studied these aspects of male mate-guarding behavior in two closely related, thermal-spring isopods (Thermosphaeroma). First, guarding duration showed species specificity which was related to the duration of reproductive cycle; cycle length for females and duration of guarding by males in T. milleri were twice as long as in T. thermophilum. Second, males in both species adjusted their guarding duration with sex ratio, guarding longer when a competing male was present. Third, in T. thermophilum, ovarian development began immediately after the birth of the previous brood and continued through guarding, sexual molt and post-molt periods until oviposition, whereas in T. milleri, ovarian development was largely postponed until the post-molt period. Because guarding during ovary provisioning periods may be costly for females, we tested the existence of intersexual conflict over guarding duration in T. thermophilum. We compared the duration of guarding of control pairs with those of pairs in which either male guarding ability or female ability to resist guarding was reduced experimentally. Guarding durations for manipulated and control males were equal, but manipulated females were guarded longer, suggesting that conflict exists and that females can effectively shorten guarding duration by their behavior. Moreover, we suggest that selection in the context of intersexual conflict may play an important role in the evolution of delayed oviposition and sperm-storage organs in mate-guarding crustaceans.