栗山天牛成虫触角感器形态与分布观察

栗山天牛Massicus raddei(Blessig)是我国东北林区栎树的主要蛀干害虫,严重危害蒙古栎和辽东栎,已给发生地造成的重大的经济损失和生态灾害。触角是天牛与外界进行信息沟通的重要器官,触角上的感器类型与分布数量直接影响天牛对外界化学刺激的识别。本文采用扫描电镜观察的方法,对栗山天牛雄、雌虫的触角分别进行了观察。结果显示,栗山天牛雌、雄性触角的感器分布略有不同,但都着生有大量的毛形感器、锥形感器和耳形感器,以及少量的板形感器、指形感器和钟形感器等。鞭节端部各节的感器数量较多,基部各节的感器数量较少,可能与各节所行使的功能有关。     

雌性信息素在麻点豹天牛成虫交尾行为中的作用

通过对麻点豹天牛Coscinesthes salicisGressitt成虫交尾行为的观察,发现雌、雄成虫间明显存在着性引诱物质的诱导现象,作者采用溶剂从雌虫体上提取出该物质,并对其生物活性及雄虫的感应方式进行检测,结果证明该信息素提取物在成虫的交尾行为中起着较为关键的作用,雄虫依靠此信息物来寻找和识别雌虫。应用提取物对雄虫所诱发的交尾行为反应与正常状态下的行为相似,经测定雄虫对该性信息素提取物的感应方式主要是接触感应。     

松墨天牛是否存在雌性接触信息素?

将松墨天牛MonochamusalternatusHope的身体不同部位切除之后的交配试验显示,分别剪去头部、鞘翅以及前胸部后仍然可以正常交配,用雄虫的腹部代替雌虫的腹部后,仍然能够引起雄虫的交配趋势动作,但不能完成真正交配,因此推测雌性接触信息素如果存在,主要集中在雌虫身体后半部,尤其是中后胸部位。但是冻死后的雌虫不再引起雄虫的交配行为,而且冻死的雌虫与活雌虫同时放入培养皿中,雄虫喜欢与活雌虫交配,不选择冻死的雌虫,因此推测视觉在其松墨天牛的交配过程中扮演着重要的角色,而接触性信息素有可能并不存在。将雄虫的触角分别从第5~6节和第1节剪去的试验结果显示,雄虫仍然可以很快地找到雌虫,发生交配行为。这有2种可能的解释一是雄虫不仅仅靠触角来感受雌虫的接触信息素,头部下颚须和下唇须上或者足上也有可以感受信息素的感受器;二是雌虫不存在接触信息素,雄虫通过视觉就可以找到对方,完成交配过程。浸泡致死的雌虫不再引起雄虫的交配行为,并且将正己烷和乙醚的浓缩液滴加在浸泡致死的雌虫以及玻璃棒和鹅卵石的生测试验结果显示,都没有引起雄虫的交配行为。这进一步说明,松墨天牛可能并不存在体表接触信息素。性成熟后的松墨天牛雌雄成虫是靠衰弱寄主的强烈的挥发性气味聚集到寄主树干上,在树干这个较为狭小的环境里,有可能是通过视觉找到配偶,完成交配过程。     

栗山天牛成虫取食、交配和产卵行为

通过室内配对饲养和野外观察,本文研究了栗山天牛成虫的取食、交配和产卵行为。结果表明:栗山天牛成虫吸食从栎树树皮受伤处溢出的汁液补充营养。栗山天牛雄成虫比雌成虫更具攻击性,在取食和交配中的雄成虫易发生争斗,交配中的雄成虫攻击性最强。其攻击方式主要是用上颚咬住对手的触角或者足进行拖拽。70%的栗山天牛雄成虫争斗是为了争夺配偶,其次是为了争夺食物资源。栗山天牛成虫完成一次完整的交配经过4个阶段,即:识别、追逐-攀附、抚慰-插入输精-交尾间歇、配后保护。整个交配过程最长可达2 h。试探性插入、插入输精和输精后保护是整个交配过程的重点,持续时间长短不一。雄成虫输入精子的次数与交配持续的时间成正比。雄成虫每次插入输精持续的时间与次数成反比,每次输精间歇时间与次数成正比。雄成虫输入精子之后会再次插入保护,平均持续约1 min。栗山天牛雌成虫产卵于寄主树皮裂缝中。以上研究为了解栗山天牛成虫的行为及其防治提供参考。     

锈色粒肩天牛触角感器的扫描电镜观察

利用扫描电镜对锈色粒肩天牛Apriona swainsoni雌、雄成虫触角上的感器结构、分布及数量进行观察和研究。结果表明:锈色粒肩天牛成虫触角鞭节状,由柄节,梗节和9节鞭节组成。在雌、雄成虫触角上分布着4类8种感器,分别是2种毛形感器,2种刺形感器,3种锥形感器和1种芽形感器。而发锥形感器和短刺形感器只分布于雄虫的触角上,不同类型感器在雌、雄个体上的长度及分布数量不同。     

专用黑光灯对栗山天牛的诱杀技术研究

栗山天牛Massicus raddei (Blessig)是我国东北林区发生面积最大的林业害虫,造成了严重的经济和生态损失.为探索诱杀栗山天牛的有效技术措施,本研究利用自主研发的专用黑光灯对栗山天牛成虫进行了诱杀技术试验研究.结果表明,将黑光灯设置在山脊是诱集栗山天牛的最佳位置;20:00～22:00是引诱的最佳时间;以天牛成虫羽化前期和末期的雄虫略多,而盛期雌虫略多,但差异不显著.诱集到的雌虫的怀卵量前期和盛期平均30粒/头,和处女雌虫无明显差异,表明诱集到的雌虫为卵刚成熟而未产出的发育阶段的成虫,而在羽化末期诱到的雌虫怀卵量不足10粒/头.和普通手电相比,该专用黑光灯的诱集数量是其2.03倍.晴天诱到的成虫数量远多于阴天.用专用黑光灯诱杀栗山天牛成虫效果显著,将在降低该害虫后代的种群数量上发挥重要作用.     

松墨天牛成虫对寄主颜色的视觉选择研究

为验证视觉信息在松墨天牛Monochamus alternatus Hope成虫寄主选择中的作用,并探索其对寄主健康状况的偏好,本文通过林间对寄主云南松针叶的色彩比对,选取国际标准色卡对应卡色作为视觉信号源,对松墨天牛雌、雄成虫的视觉选择进行了研究。研究表明,松墨天牛雌虫选择最多的颜色分别是:棕红色(选择率26.67%),赭石棕(选择率20.00%),栗棕色(选择率16.67%);松墨天牛雄虫选择最多的颜色为:信号褐(选择率26.67%),棕红色(选择率23.33%),栗棕色(选择率20.00%)。雌、雄成虫均偏好选择棕褐色系,对应于林间衰弱和濒死寄主针叶呈现的颜色,说明松墨天牛成虫通过视觉判断偏好攻击长势衰弱的林木,属于次期性蛀干害虫。     

嗜虫书虱触角的超微结构及其在交配行为中的作用

研究嗜虫书虱触角的超微结构及其在交配行为中的作用,对于其生物学和行为学具有重要的意义。本研究利用Quanta 250型扫描电镜对嗜虫书虱触角超微结构进行研究,在Lei CAEZ4HD型解剖镜下用WPI500374型显微剪刀分别剪去雌、雄虫触角及触角不同部位后,利用Smartzoom 5型超景深显微镜观察其交配行为。研究结果表明,嗜虫书虱雌、雄虫触角形态类似,均属于线状触角,由柄节、梗节和鞭节组成,鞭节分13个亚节,成虫触角感受器主要有微毛形感受器、刺形感受器(SC1、SC2)、锥形感受器(SB1、SB2)和B9hm氏鬃毛4类感受器6种形态,绝大部分触角感受器分布在雌雄触角的背面、腹面和外侧面,两性间触角感器的类型和分布无明显差异,但数量差异明显(雌、雄虫感受器的数量分别约为8280和7240)。嗜虫书虱触角在交配行为中起到重要的作用,其中雌虫触角的梗节在交配过程中起主要作用,其次是柄节,再次是鞭节;雄虫触角的鞭节部位起着主要的作用,其次是柄节和梗节。结合其交配行为并参考其他昆虫触角感受器的研究结果,推测雌虫触角柄节和梗节上分布的B9hm氏鬃毛和雄虫触角鞭节上分布的微毛形感受器在两性识别中起着主要作用,雌、雄虫触角上分布的两种刺形感受器(SC1、SC2)和两种锥形感受器(SB1、SB2)在交配过程中有机械感受的作用。本研究结果为嗜虫书虱的行为生物学、化学生态学和电生理学的研究提供参考。     

一种斑翅果蝇寄生蜂的交配行为观察及雄虫交配次数对繁殖的影响

【目的】明确一种斑翅果蝇寄生蜂Trichopria drosophilae的交配行为以及雌雄蜂的交配次数对后代的影响。【方法】在室内对斑翅果蝇寄生蜂的交配行为进行观察,记录该蜂在交配行为中所出现的求偶行为、交尾前期行为、交尾行为和交尾完毕的动作及持续时间。测定寄生蜂各交配次数下的雌蜂寿命、后代出蜂总量和后代性比。【结果】寄生蜂的交配过程包括以下几个阶段:求偶,雄蜂逐渐靠近雌虫、追逐雌蜂并震动翅膀,直至爬上雌虫背部整个过程持续(50.47±85.01)s。交尾前期,雄虫头部从雌蜂的两触角中间伸出,并将触角从雌虫触角两侧向中间有规律的触碰雌虫触角,直至雌蜂打开生殖孔,整个过程持续(43.73±13.97)s。交尾,雄蜂将雄性交配器插入雌性生殖孔整个过程持续(36.28±11.03)s。交尾后期,雌虫左右甩动腹部2~3次,主动与雄虫分离整个过程持续(8.95±3.40)s。观察结果显示,雌虫一生只能交配一次,雄蜂一生交配次数在(16.54±1.37)次,最多达到19次(N=10),雄虫的交配次数对与之交配的雌蜂的寿命和后代总量无显著影响。雄蜂的交配次数对雌性后代的性比有显著影响。【结论】该寄生蜂的交配过程主要分为雄虫求偶、交尾前期、交尾、交尾后期等阶段。求偶和交尾前期阶段主要行为是雄虫追逐雌蜂、爬上雌虫背部并用触角摩擦雌虫触角。交尾阶段主要行为是雄蜂交配器插入雌性生殖孔。交尾后期主要行为是雌蜂将雄蜂甩开,是雌虫唯一主动发起的行为。随着雄蜂交配次数增加,雌蜂后代雌/雄性比降低。     

豆野螟延迟交尾和多次交尾对生殖的影响

豆野螟Maruca vitrata(Fabricius)是一种严重的泛热带豆类蔬菜害虫。本文研究了豆野螟延迟交尾和多次交尾对其生殖的影响。延迟交尾实验结果表明:豆野螟雌雄同时延迟交尾,雌雄虫的寿命、产卵量均表现为先上升后下降的趋势,但是对卵的孵化率没有显著影响;雌虫延迟交尾,随着延迟时间的增加,雌虫的寿命、产卵量、卵的孵化率表现为下降的趋势,而雄虫的寿命延迟交尾第3天达到最大值;雄虫延迟交尾,随着延迟交尾时间的增加,雌雄虫的寿命、产卵量均表现为先上升后下降的趋势,卵的孵化率随着延迟逐渐下降。多次交尾实验结果表明,随着雄虫交尾次数的增加,成功交尾率逐渐降低,用于交尾的时间延长,雌虫和相应雄虫的寿命逐渐缩短,雌虫的产卵量下降,但对卵的孵化率影响不大;豆野螟雌虫一生只交尾一次,未见到雌虫2次交尾。     

Males,but not females,perform strategic mate searching movements between host plants in a leaf beetle with scramble competition polygyny

Mate searching is assumed to be performed mostly by males, but when females benefit from multiple mating or are under risk of failing to mate, they may also perform mate searching. This is especially important in scramble competition polygynies, in which mate searching is the main mechanism of mate competition. Typically, more mobile individuals are expected to achieve higher mating success because mobility increases their probability of finding mates. If we assume individual movements are mainly explained by mate searching in scramble competition polygynies, we can investigate searching strategies by asking when individuals should leave their location and where they should go. We hypothesize that individuals will leave their locations when mating opportunities are scarce and will seek spatially close sites with better mating opportunities. We tested these hypotheses for males and females of Leptinotarsa undecimlineata, a leaf beetle with scramble competition polygyny in which both sexes are promiscuous. Individuals mate and feed exclusively on Solanum plants, and thus, individual movements can be described as switches between plants. Females were less likely than males to leave isolated plants, and both males and females moved preferentially to neighboring plants. Males were more likely to leave when the local number of females was low, and the number of males was high. They moved to plants with more females, a behavior consistent with a mate searching strategy. Females were more likely to move to plants with fewer males and many females, a behavior consistent with male harassment avoidance. Strategic movement is widely considered in foraging context, but seldom in a mate searching context. Considering that selection to minimize searching costs, maximize mating success, and minimize harassment may be ubiquitous in nature, we argue that strategic movements by mate searching individuals are likely to occur in many species.     

Complex mate searching in the satin bowerbird Ptilonorhynchus violaceus

Mate-choice studies typically focus on male traits affecting female mating decisions, but few studies seek to identify the behavioral rules females use when searching for mates. Current models suggest that females may either directly compare a set of males ("pooled comparison") or compare each male to an internal standard ("sequential-search rule") when judging the suitability of potential mates. Models also differ in other specific aspects, such as the predicted number of sampling bouts initiated and the tendency of females to return to males after previous visits. We monitored 63 female satin bowerbirds, Ptilonorhynchus violaceus, during mate sampling to reconstruct their search patterns. We found that females typically sampled several males and returned to the most attractive male for mating: a behavior consistent with the pooled-comparison tactic. Females, however, varied in the number of males sampled; some visited only one male before mating. We found that this variation can be explained by differences among females in the number of mates, the date mate searching is initiated, and long-term experience with males. Further, females were observed to initiate two distinct sampling bouts, with the rejection of most of their potential mates occurring before the start of the second sampling bout. This suggests that the choices of potential mates are narrowed prior to the second sampling bout and that the later visits may function to reconsider preliminary decisions made during the first sampling bout or to resolve decisions concerning the remaining potential mates. Our results indicate that mate searching is a complex process in which females use multiple sampling bouts to find suitable mates and in which several different factors influence their search behavior.     

Sexual Selection of Zorion guttigerum Westwood (Coleoptera: Cerambycidae: Cerambycinae) in Relation to Body Size and Color

Zorion guttigerum is a flower-visiting longhorned beetle endemic to New Zealand. Sexual selection of this species in relation to the body size and color form of different sexes was investigated in the field. The population sex ratio, based on censuses of feeding and mating sites (flowers), is male-biased. Females are significantly larger than males. Both sexes have antennae of similar length but the antennal length relative to the elytral length is greater in males than in females, and the antennal length of males increases more with an increase in body size than that of females. Both sexes have dark blue (DB) and yellowish-brown (YB) individuals. Both pair-bonded and solitary males are similar in elytral and antennal length. In pair-bonded males, DB individuals are significantly more numerous than YB ones, but in solitary males, the number of both color forms is similar. Males tend to have territory protection behavior, fighting with and chasing away rival males from feeding and mating sites. Larger males usually win the fight but the size-dependent fighting advantage does not translate into mating success. Male color plays an important role in mating success, with DB males having a significantly better chance to mate than YB males. Furthermore, male body size and color also have interactions in mating success: males of DB color morph obtain a greater mating advantage according to body size. Pair-bonded females are significantly larger and have longer antennae than solitary females, suggesting that males prefer larger females for mating. In addition, females of DB color morph with longer antennae are also preferred by males for mating. The significance of these findings is discussed.     

Effects of a parasitic nematode on male mate choice in a livebearing fish with a coercive mating system (western mosquitofish, Gambusia affinis)

I examined the effects of the parasitic larval nematode, Eustrongylides ignotus, on male mate choice in the western mosquitofish, Gambusia affinis. I hypothesized that parasite presence influences male mate choice either directly (via reduction in male mating behavior due to presence of parasite in females) or indirectly (via reduction in male mating behavior due to reduced condition of infected females). Specifically, I tested the predictions that (1) males would mate preferentially with uninfected over infected females (scoring both mating attempts and association time with females); (2) parasitized females would be in poorer condition than non-parasitized females (measured as soluble fat stores); and (3) parasitized females would have reduced fecundity (measured as number of developing embryos). Males preferred to mate with non-parasitized over parasitized females, but showed no differences in association time between females. The nematode did not decrease female body condition, but did decrease female mass, and appeared to decrease female fecundity via reduction in broods (# embryos). Results support that parasites affect male mate choice in mosquitofish; however, the mechanisms used by males to differentiate between parasitized and non-parasitized females remain untested. This study provides the first empirical evidence of parasite affects on male mate choice in livebearing fishes, and suggest a potentially important role for parasite-mediated sexual selection in organisms that use coercive mating as the primary mechanism of obtaining mates.     

Flagellar setae of the second antennae in decapod shrimps: sexual dimorphism and possible role in detection of contact sex pheromones

Summary

The antenna 2 (antennal) flagella of decapod shrimps are chemotactile, and their setae are proposed as sensilla involved in recognition of females by males via a contact sex pheromone on the surface of the female. Male recognition of females receptive to mating occurs in many caridean species upon contact of male antennal flagella with the surface of a newly molted parturial female. The hypothesis of sexual dimorphism in the number and kind of setae on the antennal flagella of four caridean and one penaeid shrimp species was tested with setal counts and observations on setal morphology. Unique male antennal setae (“male-specific sensilla”) were not identified in any of the species investigated. However, the abundance of antennal setae was significantly greater in males than in breeding females in the palaemonid carideans Palemonetes pugio and Macrobrachium ohione. In the hippolytid caridean Thor manningi and alpheid caridean Alpheus normanni, no sexual dimorphism in setal abundance was demonstrated. In the penaeoid Rimapenaeus similis, males had a higher abundance of antennal setae than the larger breeding females but so did juvenile females, similar in size to males. The sexual dimorphism in antennal sensilla in the palaemonid species and its absence in A. normanni might be related to their different mating systems, but no such association is suggested for T. manningi and R. similis. Setal morphology suggestive of chemoreceptive function (a terminal pore) was observed in all species.     

Mate Sampling and Assessment Procedures in Female Pied Flycatchers (Ficedula hypoleuca)

Models of mate sampling strategies predict that choosiness should decrease throughout the breeding season due to increasing costs of delaying mating. Therefore, individuals who start searching mates relatively late, should spend less time on sampling, and sample fewer candidates compared to early individuals. We observed mate searching behavior of female pied flycatchers (Ficedula hypoleuca) by radio-tracking in study areas with 6–12 unpaired males. Contrary to the prediction, the observed numbers of males sampled by the searching females increased with time, i.e. late arriving females visited more males than early arrivers. However, this seems to be due to more active sampling of males in short time by late-arriving females. The observed sampling pattern suggests some kind of comparison tactic, which seems, however, to be very variable among individual females. Mate-assessing females were characterized by a remarkably cryptic behavior, which may be 1) a way of gaining honest information about the male mating status or male/territory quality, or 2) a way of avoiding courtship costs.     

Preliminary investigation of the digestive enzymes in Pagellus erythrinus (Linneo 1758) larvae

To gain a better understanding of the role of the olfactory system in sexual selection, we conducted a series of behavioral assays to correlate the number of aesthetascs with pre-copulatory behavior and male mating success in a protandrous simultaneous hermaphroditic shrimp, Lysmata wurdemanni. We demonstrated that male pre-copulatory behavior and mating success were closely associated with the number of aesthetascs. Individuals with a higher numbers of aesthetascs started approaching/searching females earlier and had higher mating success than ones with lower numbers. Sexual selection theory predicts that small males in a pure searching mating system have advantages to mate with females because they are cryptic and agile. However, our results show that aesthetasc number, rather than shrimp size, may be the major factor in determining male mating success.     

Olfactory Sex Attraction and Mating Behaviour in the Pine Sawyer Monochamus galloprovincialis (Coleoptera: Cerambycidae)

The pine sawyer Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is a vector of the pine wood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle. Male and females of this species have a kairomonal attraction to host volatiles and Ips semiochemicals. Once on the host tree, males and females copulate and oviposition occurs. Bioassays using Y-tube olfactometry revealed that females were attracted to volatile compounds produced by males, but not to volatiles produced by females. However, immature males did not seem to release attractants for mature females and immature females did not show any attraction for mature males. A experiment designed to know about mating behaviour in this specie revealed that most of the males encountered females while they were walking. In all pairs both sexes contacted with antennae before copulation, however, in some occasions copulation did not proceed just after antennal contact. On the contrary, in all pairs observed, the male licked the elytra of the female with his mouth palpi just before copulation (licking); immediately afterwards, the male grabbed the female with his forelegs and mounted her suggesting a chemically mediated mate recognition by males.     

Why do ovigerous females approach courting males? Female preferences and sensory biases in a fiddler crab

Perceptual biases explain the origin and evolution of female preference in many species. Some responses that mediate mate choice, however, may have never been used in nonmating contexts. In the fiddler crab, Uca mjoebergi, mate‐searching females prefer faster wave rates and leading wave; however, it remains unclear whether such responses evolved in a mating context (i.e., the preference has effect on the fitness of the female and her offspring that arise from mating with a particular male) or a nonmating contexts (i.e., a female obtains direct benefits through selecting the male with a more detectable trait). Here, we compared the preferences of mate‐searching with those of ovigerous females that are searching for a burrow and do not concern about male “quality.” Results showed that as both mate‐searching and ovigerous females preferentially approached robotic males with faster wave rates. This suggests that wave rate increases detectability/locatability of males, but the mating preference for this trait is unlikely to evolve in the mating context (although it may currently function in mate choice), as it does not provide fitness‐related benefit to females or her offspring. Wave leadership, in contract, was attractive to mate‐searching females, but not ovigerous females, suggesting that female preference for leadership evolves because wave leadership conveys information about male quality. We provide not only an empirical evidence of sensory biases (in terms of the preference for faster wave), but the first experimental evidence that mating context can be the only selection force that mediates the evolution of male sexual traits and female preference (in terms of the preference for leading wave).