似刺鳊鮈的两性异形和雌性个体生育力

测定了似刺鳊鮈成体的两性异形和雌性个体生育力。结果表明，雌性个体的体长显著大干雄性个体。特定体长的雌性个体的头长、眼后头长、眼径显著小于雄性个体，眼间距、体高、腹鳍基前距大干雄性个体，其他的局部特征不存在显著的两性异形。成体15个形态特征变量的主成分分析（Eigenvalue≥1）发现，前二个主成分共解释55．4％的变异。头长、头宽和眼后头长在第一主成分有较高的正负载系数，体高在第二主成分有较高的正负载系数。雌雄两性在第一和第二主成分的分值差异显著。似刺鳊鮈的怀卵数量与体长和体重回归关系显著，雌性通过个体的增长增加其个体生育力。     

花[鱼骨]的两性异形和雌体繁殖输出

测定了花（鱼骨）成体的两性异形和雌体繁殖输出.结果表明,两性成体的体长差异不显著.特定体长的怀卵雌性个体的体高显著大于产后雌体和成年雄体,产后雌体的头宽、头高、尾柄长、尾柄高大于怀卵雌性和成年雄性,产后雌体的尾鳍长、腹鳍臀鳍间距则相对较小,其它局部形态特征不存在显著的两性差异.主成分分析（Eigenvalue≥1）发现,前三个主成分共解释57.7%的变异.头长、腹鳍基前距在第一主成分有较高的正负载系数,头宽、尾柄长、尾柄高在第二主成分有较高的正负载系数,眼间距在第三主成分有较高的正负载系数.第一和第二主成分分值的组间差异显著,第三主成分分值组间差异不显著.花（鱼骨）雌体通过个体大小的增加和腹部形态的改变增加繁殖输出.     

温州厚唇鱼形态特征的两性异形和雌性个体生育力

测定了温州厚唇鱼形态特征的两性异形和雌性个体生育力。结果表明,成体和幼体雌雄两性个体的体长无显著差异。特定体长的雌性幼体的头长、吻长、眼径、腹鳍基前距和体重大于雄性幼体。特定体长的雌性成体的头高和尾柄高小于雄性成体,腹鳍臀鳍间距大于雄性成体。成体和幼体的两性间其他局部特征不存在显著的两性异形。8个形态特征变量的主成分分析(Eigenvalue≥1)发现,前3个主成分共解释65.6%的变异。头长、吻长和腹鳍基前距在第一主成分有较高的正负载系数,尾柄高和体重在第二主成分有较高的正负载系数,腹鳍臀鳍间距在第三主成分有较高的负负载系数。成幼体和雌雄两性之间在第一、第二和第三主成分的分值差异显著性,雌性在第一主成分的分值显著大于雄性,在第三主成分的分值显著小于雄性;第一、二主成分的分值2因素的相互作用显著;其余主成分分值的各因素的影响和相互作用不显著。温州厚唇鱼的怀卵数量与体长和体重回归关系显著。偏相关分析表明,怀卵数量与体重呈显著的正相关,怀卵数量与体长相关不显著。雌性通过个体大小特别是体重的增长来增加个体生育力,提高繁殖输出。     

Morphological analysis of a deep-sea whelk <Emphasis Type="Italic">Buccinum tsubai</Emphasis> in the Sea of Japan

ABSTRACT:   Morphometrical analyses were performed on Buccinum tsubai , a deep-sea gastropod found in the Sea of Japan, and morphological differences were examined between the gender and among the four local subpopulations of Hokkaido, Yamagata-Toyama, the Yamato Bank, and San'in which are distinguished by mitochondrial DNA sequence analysis. As a result, sexual dimorphism of B. tsubai was found. Morphological differences were also recognized among four areas which may be related to genetic differences. They are also thought to be associated with the phenotypic plasticity in response to different environmental factors in each area. B. tsubai inhabits the the upper portion of the Sea of Japan Proper Water (UJSPW); and in the UJSPW of the Yamato Basin, nutrients are comparatively abundant and the dissolved oxygen content is low. Such environmental differences may be related to morphological differences among the four areas.     

Growth and reproductive performance of broodstock shrimp reared in a biosecure recirculating aquaculture system versus a flow-through pond

Over the past decade, viral pathogens have caused mass mortalities of farmed shrimp throughout the major shrimp farming regions of the world. In addition, the global shrimp farming industry has been criticized for negatively impacting coastal environments. These issues have raised concerns about the sustainability of traditional shrimp farming practices, and have prompted farmers and researchers to develop biosecure technologies that promote a sustainable industry. Current technologies include the use of specific pathogen free (SPF) shrimp that are grown to market size in recirculating systems that rely on pathogen exclusion. Inherent in this approach is the need to produce SPF broodstock under biosecure conditions. However, there is a paucity of information on broodstock growth and reproductive performance when they are reared in recirculating systems. The present investigation compares shrimp growth and reproductive performance in two trials where shrimp were cultured from market size (20 g) to broodstock size (40–60 g) in a recirculating aquaculture system (RAS) versus a flow-through earthen pond (EP). In trial 1, mean growth rates of males and females in the RAS were 0.83 and 1.33 g/week, respectively. In the EP, males and females grew 1.07 and 1.48 g/week, respectively. In trial 2, mean growth rates of males and females in the RAS were 0.90 and 1.53 g/week, respectively, whereas in the EP, males and females grew and 1.24 and 1.78 g/week. Slower growth rates in the RAS may be attributed to the lack of natural productivity, which provides supplemental nutrition to the shrimp. In addition to growth rates, reproductive performance of broodstock reared in the RAS was compared with historical reproductive performance of broodstock reared in the EP. Data on spawning success and production of viable nauplii revealed no significant differences (P>0.05) between broodstock shrimp reared in these two systems. These results indicate that broodstock shrimp can be cultured in a biosecure RAS while maintaining good growth and high survival. In addition, reproductive performance of broodstock shrimp reared in a RAS is not compromised when compared with broodstock shrimp reared in a conventional, flow-through pond.     

Populations in a Transvaal Lowveld Nature Reserve

Cape sugarbirds (Promerops cafer) are the largest nectarivores in the Western Cape and feed almost exclusively on protea nectar and associated arthropods. Helderberg Nature Reserve, Western Cape, South Africa, has a large diversity of Protea and supports breeding sugarbirds. As part of a larger study, we captured sugarbirds using mist-nets during the breeding and non-breeding season at several sites in the Helderberg Nature Reserve, Western Cape, South Africa, from 1996 to 2000. From these data (n =283 males, 272 females), we found that in both sexes, individuals with longer tails have longer wings. Males were significantly larger in mass, culmen, head, tarsus, wing and tail length than females. Males with larger mass were larger in all morphometric measurements than those with smaller mass. Mate choice and territory defence may be based on wing and tail ornament displays of male sugarbirds, thus larger males with larger ornaments could benefit through greater breeding success than smaller males.     

异形狭果鹤虱的二型性种子萌发特性及其生态适应

[目的]研究异形狭果鹤虱种子的二型性现象.[方法]通过形态、扩散特征,观察和萌发实验对异形狭果鹤虱的二型性种子进行研究.[结果]长刺小坚果与短刺小坚果的刺长、百粒重存在显著差异,长刺小坚果在扩散中占优势,种子的传播距离与种子萌发率均成正相关.两者的萌发率也存在显著差异,且长刺小坚果对短刺小坚果的萌发存在抑制作用.异型种子都存在萌发休眠现象,短刺小坚果在不同温度下的萌发率变化较小,延长储藏时间可以提高异型种子的萌发率.[结论]异形狭果鹤虱种子二型性扩大了种子萌发的时间范围,增加对环境条件的适合度,有利于其在高度严酷的环境中成功定居和繁衍.     

Differential response of male and female Diabrotica speciosa (Coleoptera: Chrysomelidae) to bitter cucurbit-based toxic baits in relation to the treated area size

Cucurbitacin-rich extracts are phagostimulants for both male and female Luperini, but field trials reveal that males are far more attracted to them than females. The sex ratio and number of beetles killed by an application of cucurbitacin-based toxic baits was assessed at two different scales: small areas of 100 m², and a larger area of 10,000 m². The small area bait applications killed mostly males (95.2%), but the 1-ha treated plot showed a lower sexual bias (57% male). An earlier study indicated point sources (sticky traps) attracted only males. Results indicate that the distance attraction to bitter cucurbit extracts is almost exclusive to males, but the wide dispersal of a toxic bait based on them should promote encounter and control of both sexes within the treated area. No significant non-target effects were observed.     

Development of a Nondestructive Method for Sexing Live Adult Sternoplax souvorowiana (Coleoptera: Tenebrionidae)

The darkling beetle, Sternoplax souvorowiana (Reitter) (Coleoptera: Tenebrionidae), is flightless and lives in the Guerbantonggut desert in northwestern China. Its special eggshell structure, day-active habit, large body size, short life cycle, and ease of rearing under laboratory conditions make it an excellent model for advanced studies on desert adaptation. Determining the sex of this beetle is usually complicated by the lack of a discreet, externally visible gender-specific character. To date, dissection has been used for sex identification in this species, whereas a nondestructive means is needed for further studies of sexual dimorphism. Here, a new method based on the difference of the pigmentation pattern on the eighth tergite of each sex is described and illustrated. This method can be quickly learned, is nondestructive, is 100% accurate, and is fast enough for most applications in both the field and the laboratory. Experienced users in our laboratory routinely sex 8–10 beetles per minute.     

Body Size,Rather Than Male Eye Allometry,Explains Chrysomya megacephala (Diptera: Calliphoridae) Activity in Low Light

Male Chrysomya megacephala (F.) blow fly compound eyes contain an unusual area of enlarged dorsal facets believed to allow for increased light capture. This region is absent in females and has been hypothesized to aid in mate tracking in low light conditions or at greater distances. Many traits used in the attraction and capture of mates are allometric, growing at different rates relative to body size. Previous reports concerning C. megacephala eye properties did not include measurements of body size, making the relationship between the specialized eye region and body size unclear. We examined different morphological features of the eye among individuals of varying sizes. We found total eye size scaled proportionately to body size, but the number of enlarged dorsal facets increased as body size increased. This demonstrated that larger males have an eye that is morphologically different than smaller males. On the basis of external morphology, we hypothesized that since larger males have larger and a greater number of dorsally enlarged facets, and these facets are believed to allow for increased light capture, larger males would be active in lower light levels than smaller males and females of equal size. In a laboratory setting, larger males were observed to become active earlier in the morning than smaller males, although they did not remain active later in the evening. However, females followed the same pattern at similar light levels suggesting that overall body size rather than specialized male eye morphology is responsible for increased activity under low light conditions.