竹横锥大象对寄主及虫体挥发物的行为和触角电位反应

为了探明竹横锥大象Cyrtotrachelus buqueti Guerin-Meneville是否存在两性间的引诱作用,以及寄主植物慈竹Neosinocalamus affinis笋对两性行为的影响,采用Y型嗅觉仪测定了竹横锥大象雌、雄成虫对4种虫体及寄主挥发物不同处理（雌、雄成虫,慈竹笋与雌、雄成虫的复合体）的行为反应,测定了触角不同部位对雌雄成虫3种虫体的提取物（整体、鞘翅、后肠）及其与寄主植物挥发物质联合作用的触角电位反应（EAG）。结果表明：雌成虫挥发物对雄虫有较高的引诱活性,对雌虫有驱避作用;雄成虫挥发物对雌虫有一定的引诱作用。雌、雄成虫对虫体与竹笋复合体气味的行为和电生理反应均显著或极显著高于对相应虫体挥发物的反应。经EAG测定,触角各部位对虫体不同部位挥发物的EAG值差异明显,触角端部对虫体与植物挥发性物质的联合作用EAG反应差异极其显著（P＜0.01）。竹横锥大象对沾染雌雄成虫虫体提取物的玻璃棒有一定的兴奋表现,雌虫兴奋率为6.67%,雄虫为26.67%。结果提示,竹横锥大象种内存在信息素,雌虫释放的信息素对同类雄虫有很强的引诱作用,而雄虫所释放的信息素对同类雌虫有引诱作用,添加寄主植物能够增强两性间的引诱效果。     

豆野螟成虫行为学特征及性信息素产生与释放节律

豆野螟Maruca vitrata (Fabricius)是一种严重的泛热带豆类蔬菜害虫。本文在（29±1）℃、相对湿度75%～80%、光周期14L∶10D条件下研究了豆野螟成虫的羽化、交尾行为以及雌蛾性信息素的释放节律。结果表明：其羽化行为全天可见,在雌蛾中,86%于暗期羽化; 在雄蛾中,73%于暗期羽化。雌雄蛾羽化行为在暗期第4、5和8 h差异达到显著 (t>4; P<0.05)。交尾活动发生在暗期19：00到5：00之间,交尾持续时间最短约为20 min,最长约为90 min,3日龄进入暗期第5 h具有最高的交尾率。1、6和7日龄成虫具有单个交尾高峰,2到5日龄成虫具有两个交尾高峰。同一日龄成虫交尾在暗期前半段平均花费的时间要明显高于在后半段花费的时间。低龄和高龄的成虫用于交尾的时间明显高于中龄的性成熟成虫。成虫的开始交尾时间随着日龄的增加逐渐前移。雄蛾对进入暗期后第5 h和第9 h处女雌蛾的性腺提取物和空气收集性信息素的触角电位反应最强,对 3日龄处女雌蛾的性腺提取物和空气收集性信息素的触角电位反应最强。处女雌蛾田间诱蛾试验表明：23：00-01：00为诱蛾高峰期,3日龄处女雌蛾的诱蛾效果最好。该蛾的羽化、交尾及性信息素产生与释放均存在节律上的一致性。雌蛾的性信息素释放的时间较长,见于整个暗期,然而交尾行为发生时间较短,主要发生于两个交尾高峰之间。     

酪蝇雌虫卵巢提取物对其雄虫的引诱效果

【目的】本文研究目的是验证酪蝇Piophila casei雌虫卵巢是否存在性信息素,并为酪蝇性信息素研究提供科学依据。【方法】测定了酪蝇雄虫对不同剂量的雌虫卵巢提取物的行为选择反应和触角电位反应,还利用模拟仓储实验测定了不同剂量的雌虫卵巢提取物对酪蝇雄虫的诱捕效果。【结果】当酪蝇雌虫卵巢提取物的剂量分别为0.5、1、1.5、2、2.5头当量时,雄虫对0.5、1、1.5头当量的雌虫卵巢提取物有选择反应,雄虫对这5个剂量的雌虫卵巢提取物均具有触角电位反应。酪蝇雌虫卵巢提取物对雄虫诱捕效果的模拟仓储实验结果显示:当酪蝇卵巢提取物的剂量分别为2、4、6、8、10头当量时,在非选择性实验中各当量的雌虫卵巢提取物对雄虫均有引诱效果,在选择性实验中雌虫卵巢提取物的剂量为2头当量时,对雄虫的引诱效果最好。【结论】酪蝇雌虫卵巢提取物对雄虫有显著的引诱效果,表明酪蝇雌虫卵巢中存在吸引雄虫的化学成分,即酪蝇的性信息素。     

长足大竹象体表信息化学物质的释放节律及对成虫的EAG与行为反应

为了研究长足大竹象成虫体表挥发性物质的日节律变化,揭示体表挥发性物质对长足大竹象成虫行为的影响。实验选用Tenax-TA吸附剂吸附法结合气相色谱一质谱联用技术(GC-MS)分析了长足大竹象雌雄成虫体表挥发物质的日节律变化,利用触角电位仪比较了未交配雌、雄成虫对挥发物的EAG反应,并采用Y型嗅觉仪进行成虫行为生测。结果表明:长足大竹象雌雄成虫挥发性物质主要由烷烃类、烯烃类、脂类、醇醛酚类等物质组成,雌虫的体表挥发性物质有20种,雄虫的体表挥发性物质有18种;10∶00-12∶00时间段雌虫节律性挥发物对未交配雄虫的引诱率最高(P0.05),与其EAG反应值一致,而雄虫不同时间段体表挥发物对雌雄成虫有一定的引诱作用,这与行为反应结果一致。本研究结果表明10∶00-12∶00为长足大竹象释放信息素的高峰期,这为长足大竹象信息素的有效提取和分离提供可靠依据。     

异迟眼蕈蚊成虫行为学特征及性信息素初步研究

【目的】为了寻求高效无污染的防治害虫异迟眼蕈蚊Bradysia difformis Frey的方法。【方法】本文在人工气候室条件下,采用行为、化学生态学等研究方法,系统观察了异迟眼蕈蚊的羽化节律、交配行为,并对其性信息素进行了初步研究。【结果】异迟眼蕈蚊羽化没有明显的昼夜节律,雌虫在16:00—21:00达到羽化高峰,雄虫羽化高峰出现在17:00—23:00,成虫在光期的羽化数量占总羽化数量的72%。成虫的求偶交配行为多发生在羽化后10 min左右,交尾时间3 min左右。异迟眼蕈蚊雄成虫在"Y"型嗅觉仪中对雌成虫及雌成虫腹部粗提物具有正趋向行为反应(P<0.01),证明异迟眼蕈蚊雌虫释放性信息素。【结论】通过气相色谱-质谱联用仪(GC-MS)对雌、雄成虫腹部粗提物进行化学分析,得到雌成虫特有的3种化学物质:正十二烷、正十六烷酸、(Z,Z)-9,12-十八烷二烯酸,这些化合物可能是异迟眼蕈蚊雌成虫的性信息素成分。     

亚洲柑橘木虱成虫在九里香上的取食与交尾行为观察

【目的】深入了解亚洲柑橘木虱Diaphorina citri Kuwayama的生物学习性,为有效防治和阻止其传播黄龙病提供依据。【方法】利用昆虫行为观测仪对雌、雄成虫在九里香上的取食、交尾行为进行观察,比较雌、雄成虫在嫩梢和成熟梢上取食行为的差异。【结果】雌、雄成虫在嫩梢和成熟梢上总的取食时间都没有显著差异。但是,雌成虫在成熟梢上的取食时间显著长于在嫩梢上,而雄成虫没有显著差异。在嫩梢上,雌雄成虫都更倾向于取食嫩茎,其次为叶片,叶柄上最少,其中雌成虫在嫩茎上取食时间显著长于叶片和叶柄。在成熟梢上,雌成虫在叶背的取食时间显著长于叶面和茎,而雄成虫在叶面和叶背的取食时间没有显著差异,并且在叶面的取食时间显著长于茎。交尾开始时,雄成虫将腹部末端的抱握器从雌成虫腹部下方抱住其产卵器,然后进行交尾,交尾过程中雄成虫间歇性地抖动远离雌虫的后足。交尾结束时,雄成虫先收缩腹部,使双方腹部末端下垂,呈弓型,然后雌雄成虫在合体的情况下共同行走一段距离后再分开,交尾时间持续约40 min。【结论】雌雄虫的取食行为有差异,雌虫在成熟梢上取食时间长于嫩梢且嗜食成熟叶的叶背。雌雄1次交尾持续时间约40 min。     

棉花粉蚧雄成虫对雌虫的性选择及日交配节律

研究棉花粉蚧雄成虫对不同虫态、不同日龄雌虫的性选择以及雌雄成虫日交配节律,为该虫性信息素的研究提供科学依据。采用四臂嗅觉仪测定了雄虫对不同虫态以及不同日龄雌虫(3龄若虫、1日龄至8日龄处女雌成虫、已交配雌成虫)的选择性,观察了雄虫与雌成虫日交配节律。结果表明,雄成虫对4日龄处女雌成虫的选择率显著高于其他虫态和日龄,一天内扶桑绵粉蚧交配高峰期出现在7∶00-9∶00。因此,推测4日龄处女雌成虫和上午7∶00-9∶00可能是释放性外激素的旺盛虫期和时间。     

沙柳木蠹蛾性行为及其性信息素滴度的动态节律

沙柳木蠹蛾Holcocerus arenicola是为害沙柳Salix psammophila的主要钻蛀性害虫之一。在进入暗期后的6 h内,对其求偶行为和交配行为进行观察和记录,调查该虫求偶和交配的活动规律。通过触角电位技术（EAG）和毛细管气相色谱（GC）对性腺体内信息素的滴度进行了分析,以揭示性信息素产生的昼夜节律和雌虫日龄对性信息素合成的影响。结果表明：该虫在暗期0.5~1 h内即开始有求偶行为,最大求偶高峰出现在羽化后的第2晚。交配行为主要发生在暗期的1~2 h内。在各日龄的成虫中,1日龄成虫的交配百分率最高。交配平均时间为24.16±2.64 min,随着日龄的增加,交配时间前移。在实验中,未观察到5~6日龄成虫的交配行为。沙柳木蠹蛾性信息素的体内合成早于求偶行为1~2 h,并在暗期的前2 h内达到峰值。性信息素的滴度随着雌虫日龄的增减而减少,最高值为当日羽化雌虫的腺体提取物。林间诱蛾实验中,处女雌蛾和性腺体提取物对雄蛾均有较好的诱捕效果。本研究表明,在沙柳木蠹蛾的性信息素滴度和性活动之间具有同步关系,同时为进一步利用长距离性信息素防治该虫提供了参考。     

黄褐幕枯叶蛾生殖行为研究和林间引诱试验

【目的】为探索一种高效、无污染的防治黄褐幕枯叶蛾Malacosoma neustria testacea Motschulsky(Lepidoptera:Lasiocampidae)的方法,本文对其生殖生物学特征进行了研究。【方法】本试验于2013年和2014年期间通过室外笼内人工饲养和野外调查相结合,观察黄褐幕枯叶蛾的生殖行为学特征。【结果】黄褐幕枯叶蛾羽化期40 d左右,羽化高峰在6月19日―7月03日,日羽化高峰期在17:00―19:00,雌雄平均性比为1︰(1.19±0.07),未交配雌雄成虫的平均寿命分别为(4.13±0.142)d和(4.57±0.035)d,雄蛾的寿命高于雌蛾。在凌晨0:00―3:00均能观察到雌蛾有明显的求偶行为。成虫交尾高峰在凌晨2:30左右,1日龄的成虫交尾率最高(61.67%±2.89%),随着日龄的增加成虫的交尾行为逐渐减弱。交尾持续时间最短为20 min,最长可达135 min。林间诱蛾实验中,未交配雄蛾和空白对照都没有引诱到成虫,1~6日龄未交配雌蛾均能引诱到雄虫,且1日龄未交配雌蛾诱蛾量最大,凌晨2:00―3:00是诱蛾高峰期;凌晨1:30未交配雌蛾性腺提取物的引诱量最大,1日龄未交配雌蛾性腺提取物对雄蛾的引诱效果最佳。【结论】本试验的研究结果为利用昆虫性信息素防治黄褐幕枯叶蛾奠定了基础。     

豆野螟成虫触角对植物挥发性和性信息素化合物的触角电位反应

以顺3-己烯乙酸酯为标准化合物,研究了豆野螟雌、雄成虫触角对不同浓度的植物挥发性和性信息素化合物组分的触角电位（EAG）反应.结果表明：豆野螟雌、雄成虫触角对植物挥发性气味具有强烈的EAG反应,但在大部分浓度下,雌、雄虫的反应没有显著差异.在测试的9种植物挥发性化合物中,雌、雄虫对高浓度反-2-己烯醛刺激的相对EAG反应的最大值分别达到250%和260%,且雌、雄虫触角对这种化合物的EAG反应的形状也有很大差异;但对豇豆花气味中的柏木烯和柏木脑没有明显的EAG反应.雌、雄蛾对性信息素都有明显反应,且雌、雄虫的反应存在显著差异,雄虫触角对性信息素化合物主要组分（反10,反12）-十六碳二烯醛的EAG反应的最大值达到250%,远超过雌虫反应的最大值(53%).雌、雄成虫这种神经感觉反应的差异反映了它们在感器结构、功能和行为上的差异.     

Observations on the mating behavior of the alfalfa blotch leafminer,Agromyza frontella (Rondani) (Diptera: Agromyzidae), and evidence of a female sex pheromone

The mating behavior of Agromyza frontella was studied under laboratory conditions. Adults were able to mate on the day of emergence, with no evident periodicity throughout the photophase. The host plant was essential for mating to occur, its presence affecting female receptivity rather than male copulatory behavior. Males generally entered a stationary phase once in the proximity of a female, before undertaking a final approach. This stationary behavior frequently resulted in male aggregations around a female, and under such conditions males exhibited a characteristic wing vibrating behavior. As male wing vibration was not an essential behavior for successful mating, and rarely occurred during male encounters in the absence of females or when only one male was near a female, it was considered as being primarily a male-male signal. The majority of females that mated exhibited an ovipositor pumping behavior that stimulated the male approach. However, such behavior was not essential to attract mates, as dead females elicited the entire sequence of male mating behavior. This suggested the presence of a cuticular sex pheromone, as reported for other species of higher Diptera. Whole virgin female (<24- h or 3- day-old) hexane extracts applied to male cadavers increased the time males spent on the plant, the number of contacts with the treated cadavers, the incidence of attempted copulations, and the wing vibrating behavior between males compared with controls using untreated cadavers. The results obtained indicate that females control copulation in A. frontella and that both semiochemical and visual cues are important in eliciting male mating behavior.     

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。     

The role of heliothine hairpencil compounds in female Heliothis virescens (Lepidoptera: Noctuidae) behavior and mate acceptance

Studies on numerous insect species suggest that male-produced sex pheromones play a role in attracting females; as aphrodisiacs, making females more quiescent; or as a means of inhibiting competing males. Male heliothine moths display abdominal hairpencils during courtship, but the specific effects of the odors released on female behavior have not yet been elucidated. This study investigates the role of male hairpencil compounds in female Heliothis virescens mating behavior. Female H. virescens were exposed to filter paper loaded with hairpencil extracts of male H. virescens, Heliothis subflexa and Helicoverpa zea, and observed for behavioral responses to odors. Single synthetic compounds found in the H. virescens hairpencil blend were also tested. In mating assays between single male and female H. virescens it was found that: (i) antennectomized females mated less frequently than sham-operated females; (ii) females mated less frequently with males whose hairpencils had been surgically removed; (iii) females mated with males with ablated hairpencils if a filter paper loaded with one male equivalent of H. virescens hairpencil extract was presented simultaneously; and (iv) this effect was species-specific, as presentation of H. subflexa or H. zea hairpencil extracts did not restore mate acceptance. This study suggests that odors released by male hairpencils are important in mate acceptance by female H. virescens, and may play a role in mate choice and species isolation.     

褛裳夜蛾的交配行为及雄蛾对性腺提取物的反应节律

详细观察了褛裳夜蛾成虫的交配行为,利用风洞、触角电位技术研究了雄蛾对性腺提取物的反应节律,通过林间诱蛾试验进行了验证,旨在为褛裳夜蛾性信息素的精确提取及性信息素组份分离、鉴定提供依据。研究结果表明:成虫的求偶、交配行为均发生在暗期,有一定的节律性:雌蛾在羽化3d以后开始求偶,1周左右表现最为强烈,3-4日龄雌蛾在暗期4-6h开始求偶,最大求偶率在暗期6-8h;5-9日龄在进入暗期就开始求偶,最大求偶率出现在暗期4-6h。风洞试验表明,3-7日龄的雄蛾对性腺提取物均有明显的性行为反应,5日龄雄蛾在暗期4-6h对性腺提取物的反应最为强烈。3-6日龄的成虫在暗期4-6h开始交配,而7-8日龄的成虫于暗期2-4h开始交配,6日龄的成虫交配率最高,交配高峰在暗期4-8h。雄蛾对性腺提取物的触角电位反应也有一定的节律性:雄蛾对4日龄雌蛾性腺提取物开始有电生理反应,对6-7日龄暗期5h性腺提取物反应最为强烈。林间诱蛾试验测定了性腺提取物的引诱活性,7日龄雌蛾性腺提取物林间诱蛾量最高,引诱高峰在暗期4-6h,该结果也验证了褛裳夜蛾雄蛾对性腺提取物的反应节律。     

柳毒蛾繁殖生物学的初步观察

【目的】为了明确柳毒蛾Leucoma salicis(Linnaeus)交配的日节律高峰,温度和不同交配持续时间处理对成虫寿命、产卵量和孵化率等繁殖生物学的影响。【方法】将新羽化的柳毒蛾成虫置于养虫笼中,观察交配的日节律高峰,并统计不同温度和不同交配持续时间处理下的成虫寿命、产卵量和孵化率。【结果】成虫在羽化当晚的后半夜凌晨开始交尾,次日晚上开始产卵。成虫交配集中在羽化翌日凌晨3:00—5:00之间,高峰为4:00。产卵高峰都出现在2日龄成虫,但是,25℃下成虫交配持续时间(9.2 h)显著短于28℃(11.8 h)。交配持续时间为30、60和300 min的处理,雌成虫平均寿命显著长于对照(对照9.2 h),雄虫仅60 min的处理显著长于对照。同时,极短的交配持续时间(30 min)显著降低雌虫的产卵量和孵化率。【结论】试验明确了成虫交配的日节律高峰,在适宜的温度范围内(25~28℃),雌雄成虫的寿命、单雌总产卵量无显著差异,交配持续时间明显影响成虫寿命、产卵量和卵孵化率。     

Mating Status Effects on Sexual Response of Males and Females in the Parasitoid Wasp <Emphasis Type="Italic">Urolepis rufipes</Emphasis>

Although mate preferences are most commonly examined in females, they are often found in both sexes. In the parasitoid wasp Urolepis rufipes, both female and male mating status affected certain aspects of sexual interactions. Female mating status mattered only in the later stages of mating. Males did not discriminate between virgin and mated females in terms of which they contacted or mounted first. However, once mounted, most virgin females were receptive to copulation, whereas very few mated females were. Whether a male’s mating status affected his own sexual response depended on the female’s ability to respond and the stage of mating. Examining male behavior toward dead females allowed elimination of the role of female behavior in how males responded. Virgin and mated males are both attracted to dead females as evidenced by their fanning their wings at such females. However, mated males were quicker than virgin males to contact and to mount in an experiment with dead females, whereas there was no such differential response in an experiment with live females. This difference is consistent with greater female sexual responsiveness to virgin males. Male mating status also affected female receptivity to copulate. Once mounted, live virgin females were less likely to become receptive to copulation by mated males than to virgin males, but only in a choice experiment, not in a no-choice experiment.     

Synchronous female spawning and male mating behavior in a land-locked population of Japanese charr, Salvelinus leucomaenis japonicus

In resource-based promiscuous mating systems, synchronous spawning of females affects competition among males and variation in the reproductive success of males. We documented the mating behavior of Japanese charr (Salvelinus leucomaenis japonicus) through an annual breeding season to examine the relationship between female spawning synchrony and male mating behavior. Females spawned highly synchronously in the population studied, i.e., approximately half the spawning was finished within the first three days of the entire spawning season (11 days). The daily operational sex ratio (OSR) was nearly 1:1 through the spawning period. The number of males around a spawning female was very small (1.21+/-0.49 males per female) over the spawning ground and period, suggesting that a competitive male could effectively chase subordinate males away from a spawning female. A few males attempted to sneak near the oviposition site of females (16%; 9 of 57 breeding groups), while some males adopted sneaking tactics in the initial phase of females' spawning (24%). We did not observe any males to succeed in sneak fertilizations. We conclude that in this Japanese charr population, the synchronous spawning of females was related to the unbiased daily OSR, male aggregation around females, and consequently whether and how efficiently males engaged in sneak mating behavior.     

Mate choice and sexual conflict in <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> (Rotifera)

Male mate choice in Brachionus plicatilis is based on information from coronal receptors and contact chemoreception of a glycoprotein signal on the body surface of females. Male mating behavior is modulated by mating signal quality and strength, which determines male mating persistence and circling intensity. We probe the sensory abilities of males by better resolving their discrimination of female age. Males preferentially initiate mating with young females, but not too young. Males circle 0.2 h old females just hatched from resting eggs only about 1/2 as frequently as 12 h old females. Males are even more discriminating of females with whom they copulate, preferring 3 h old females significantly more than 0.2 h or 6 h old females. In contrast, males cannot distinguish between virgin females and those who have already copulated. Similarly, males circled and copulated with females hatching from resting eggs with equal frequency as those hatching from amictic eggs. The counterpoint to male mate choice is female resistance to mating. When males contact females, the females respond with one of four behaviors: no response, acceleration, foot flipping, or coronal retraction. In 65% of male–female encounters, there was no initial response by females. However, when males began circling females, females accelerated 11.1 times more often than when males were absent. The second type of evasive female behavior was foot-flipping, which tends to knock off males attempting to circle the female. In the presence of circling males, females performed foot-flipping behavior three times more often than in the absence of males. Coronal retraction, where they stop swimming and withdraw their corona, was observed less frequently than acceleration or foot-flipping, and there was no difference in the presence or absence of males. These data are interpreted in the context of sexual conflict, where the behaviors that optimize male and female fitness differ. Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez Advances in Rotifer Research     

Do Male Veiled Chameleons,Chamaeleo calyptratus,Adjust their Courtship Displays in Response to Female Reproductive Status?

Variation in male courtship behavior may be due to inherent differences among males or may arise from males adjusting their courtship displays according to female responsiveness. Female veiled chameleons, Chamaeleo calyptratus , exhibit two distinctive suites of body coloration and behavior patterns that vary according to receptive and non-receptive stages of their reproductive cycle. We presented male chameleons with both receptive and non-receptive females, and recorded differences in their mating frequency, courtship intensity and courtship behavior patterns. As expected, males were more likely to court and attempt mating with receptive females. Although fewer males courted non-receptive females, their courtship displays were significantly longer than those directed towards receptive females. Males also adjusted the contents of their displays according to female reproductive condition. Certain behavior patterns were unique to courtship displays directed towards each class of females. Males exhibited the behavior pattern `head roll' only when paired with receptive females, and `chin rub' was displayed only during courtship of non-receptive females. We hypothesize that these differences in male courtship frequency, intensity and content reflect differences in female reproductive value. Although males may benefit from mating with both receptive and non-receptive females, the costs associated with courtship may depend on female responsiveness. Thus, males adjust their courtship tactics accordingly.     

Male Seminal Fluid Substances Affect Sperm Competition Success and Female Reproductive Behavior in a Seed Beetle

Male seminal fluid proteins are known to affect female reproductive behavior and physiology by reducing mating receptivity and by increasing egg production rates. Such substances are also though to increase the competitive fertilization success of males, but the empirical foundation for this tenet is restricted. Here, we examined the effects of injections of size-fractioned protein extracts from male reproductive organs on both male competitive fertilization success (i.e., P2 in double mating experiments) and female reproduction in the seed beetle Callosobruchus maculatus. We found that extracts of male seminal vesicles and ejaculatory ducts increased competitive fertilization success when males mated with females 1 day after the females’ initial mating, while extracts from accessory glands and testes increased competitive fertilization success when males mated with females 2 days after the females’ initial mating. Moreover, different size fractions of seminal fluid proteins had distinct and partly antagonistic effects on male competitive fertilization success. Collectively, our experiments show that several different seminal fluid proteins, deriving from different parts in the male reproductive tract and of different molecular weight, affect male competitive fertilization success in C. maculatus. Our results highlight the diverse effects of seminal fluid proteins and show that the function of such proteins can be contingent upon female mating status. We also document effects of different size fractions on female mating receptivity and egg laying rates, which can serve as a basis for future efforts to identify the molecular identity of seminal fluid proteins and their function in this model species.