褐稻虱求偶鸣声和交尾行为

褐稻虱Nilaparvata lugens(stl)成虫交尾前均发出由固体介质(寄主植株)传播的声信号,用于个体间联系。信号产生于伴随腹部振动的摩擦发声过程,具有种的专一性,能联络、识别同种异性个体,刺激性兴奋和为雄虫寻觅雌虫定向,对求偶和完成交尾具有重要意义。为害水稻的与为害李氏禾属杂草Leersia hexandra(Swartz)的生物型之间,鸣声声学特征存在明显差异,构成型间杂交的某些障碍;而为害水稻的四种生物型之间无显著差异。     

A COMPARISON OF THE LIFE CYCLES OF DEROCERAS RETICULATUM (MULLER) AND ARION INTERMEDIUS NORMAND (PULMONATA: STYLOMMATOPHORA) AT DIFFERENT TEMPERATURES UNDER LABORATORY CONDITIONS

Growth rates and life cycles of D. reticulatum and A. intermediusare described and compared at different temperatures. D. reticulatummatures earlier in the cycle than A. intermedius and is moresensitive to changes in temperature. These differences are discussedin relation to the natural life cycles and ecology of thesespecies. (Received 9 February 1981;     

褐稻虱求偶鸣声和交尾行为

褐稻虱Nilaparvata lugens(Stal)成虫交尾前均发出由固体介质(寄主植株)传播的声信号,用于个体间联系.信号产生于伴随腹部振动的摩擦发声过程,具有种的专一性,能联络、识别同种异性个体,刺激性兴奋和为雄虫寻觅雌虫定向,对求偶和完成交尾具有重要意义.为害水稻的与为害李氏禾属杂草Leersia hexandra(Swartz)的生物型之间,鸣声声学特征存在明显差异,构成型间杂交的某些障碍;而为害水稻的四种生物型之间无显著差异.     

啮小蜂视觉和触角在交配中的作用观察

本文研究了啮小蜂Tetrastichus sp.视觉和触角在交配中的作用,实验结果表明,视觉对雄蜂起重要作用,对雌蜂作用则不显著;触角在啮小蜂求偶识别和接受中起重要的作用,雄蜂柄节具有一分泌小孔,求偶的雄蜂遇到雌蜂后柄节能分泌大量的膏状渗出物,雌蜂是靠接触雄蜂触角来识别和接受雄蜂.     

DIVERGENCE IN MORPHOLOGY AND MATING SIGNALS,AND ASSORTATIVE MATING AMONG POPULATIONS OF CHORTHIPPUS PARALLELUS (ORTHOPTERA: ACRIDIDAE)

Three geographically widely separated populations of the grasshopper Chorthippus parallelus (Orthoptera: Acrididae) have been examined for morphological divergence, divergence in characteristics of the acoustic sexual signals of males, and assortative mating. Significant assortative mating existed between two of the three pairwise combinations of populations in multiple-choice tests. This may be caused by divergence in three of the four acoustic signal parameters measured. The populations also differed in morphology, including characters associated with signal production. The results are discussed in relation to theories for the origin of premating isolation, and it is argued that the observed divergence has developed rapidly, possibly indicating the action of selection. However, this selection could not have been caused by interactions with closely related taxa.     

性信息素2，6-二氯酚在长角血蜱交配行为中的作用

长角血蜱Haemaphysalis longicornis的交配行为包括7个时期,行为的完成依赖于性信息素的调节。生物测定表明：雄蜱的行为反应受雌蜱分泌的性信息素影响。堵塞雌蜱盾窝其行为受到抑制,点滴2,6-DCP或雌蜱盾窝腺提取物则被恢复。用气相色谱法测定了雌蜱盾窝腺中2,6-DCP的含量;吸血后1～２天含量最高(11.12 ng/只);吸血后3～５天即交配前下降交维持在一较恒定的水平;吸血后6～７天即交配后明显降低;饱血后检测不到2,6-DCP。2,6-DCP是长角血蜱性信息素的一种成分。     

THE SHELL-FORMING MANTLE EPITHELIUM OF BIOPHALARIA GLABRATA (PULMONATA): ULTRASTRUCTURE, PERMEABILITY AND CYTOCHEMISTRY

In the freshwater snail Biomphalaria glabrata, the outer mantleepithelium and the transitional epithelium from the outer mantleepithelium to the belt are characterized by apical vesiclesof different electron density and vacuoles including lipid dropletsand fibrillar structures. Wide intercellular spaces predominatein the transitional epithelium. In addition to belt desmosomes,freeze fracture studies detect septate junctions as apical intercellularjunctions. The permeability of the septate junctions is testedby injecting anaesthetized snails with solutions containingperoxidase and lanthanum-nitrate. The septate junctions appearto be impermeable for the protein and inhibit permeation ofthe ion. Alkaline phosphatase is detected at the light microscope levelin the transitional and outer mantle epithelium. At the electronmicroscope level localization of alkaline phosphatase is restrictedto the apical and basal cell membranes of the same epithelia.An ATPase with low affinity to Ca²⁺ and Mg²⁺ ions is observedin the lumen of vacuoles in the proximal belt, the transitionaland the outer mantle epithelium. The possible role of the vacuolesas a site of synthesis or modification of the intercrystallinematrix is discussed. A high affinity Ca²⁺/Mg²⁺ ATPase is detectedwith the help of Electron Spectroscopic Imaging in the cellmembranes and in membranes of the rER. A model for solute transport through the epithelia to the extrapallialspace is proposed. (Received 18 August 1992; accepted 4 January 1993)     

AN ULTRASTRUCTURAL STUDY OF SPERMATOZOA OF HELIX ASPERSA AND HELIX POMATIA (GASTROPODA, PULMONATA)

Spermatozoa of the pulmonates Helix aspersa Müller andH. pomatia Linnaeus are examined in detail using transmissionelectron microscopy (TEM). Important features such as the acrosome,perinuclear sheath, nucleus and terminal region of the midpieceare described for the first time. Also presented are the firstultrastructural observations on spermatozoa from spermatophoresin any pulmonate gastropod (H. aspersa). No morphological differencescould be found between sperm taken from spermatophores and thosewithin the hermaphrodite duct in H. aspersa. Spermatozoa ofH. aspersa and H. pomatia snow all the characteristics of euthyneuranspermatozoa, namely: a helically-keeled nucleus; distinctivearrangement of acrosomal components (apical vesicle, acrosomalpedestal), and extremely elongate midpiece (axoneme and glycogenhelix enclosed by matrix and paracrystalline layers). The spermnucleus of both species is short, and the midpiece also formsthe terminal portion of the spermatozoon (glycogen piece absent).The extraordinary positioning of the acrosome in H. aspersa—reflectedbackwards from the nuclear apex—is not observed in H.pomatia, though a perinuclear sheath (possibly another acrosomalcomponent) is present in sperm of both species. Helix spermatozoaare compared with other euthyneuran sperm and briefly discussedfrom the systematic viewpoint. Present address: Department of Zoology, St. Lucia, 4067, Brisbane,OLD, Australia (Received 23 May 1988; accepted 17 August 1988)     

THE INFLUENCE OF HUMIDITY, PHOTOPERIOD, AND TEMPERATURE ON THE DORMANCY AND ACTIVITY OF HELIX LUCORUM L. (GASTROPODA, PULMONATA)

The dormancy of Helix lucorum from N. Greece is controlled primarilyby low humidity. Photoperiod and temperature have no directeffect, except in the anomalous combination of long cool daysor short hot days. Adults hibernate more readily than juveniles.The duration of hibernation (before rejection of the calcareousepiphragm) is only slightly shorter at high temperatures. (Received 15 December 1985;     

SEXUAL REPRODUCTION,MATING SYSTEM,AND PROTOPLAST DYNAMICS OF SEMINAVIS (BACILLARIOPHYCEAE)1

Cell division, the mating system, and auxosporulation were studied in the marine epipelic diatom Seminavis cf. robusta Danielidis & D. G. Mann. The interphase protoplast contains two girdle‐appressed chloroplasts, each with an elongate bar‐like pyrenoid, and also a central nucleus, located in a bridge between two vacuoles. Before cell division, the chloroplasts divide transversely and translocate onto the valves. The nucleus relocates to the ventral side for mitosis. After cytokinesis and valve formation, the chloroplasts move back to the girdle, showing a constant clockwise movement relative to the epitheca of the daughter cell. Seminavis cf. robusta is dioecious, and sexual reproduction is possible once cells are less than 50 μm. In crosses of compatible clones, gametangia pair laterally, without the formation of a copulation envelope, and produce two gametes apiece. The intensity of sexualization increases as cells reduce further in size below the 50‐μm threshold. At plasmogamy, the gametangia dehisce fully and the gametes, which were morphologically and behaviorally isogamous, fuse in the space between the gametangial thecae. The auxospore forms a transverse and longitudinal perizonium. After expansion is complete, there is an unequal contraction of the protoplast within the perizonium, creating the asymmetrical shape of the vegetative cell. Apart from this last feature, almost all characteristics exhibited by the live cell and auxospores of Seminavis agree with what is found in Navicula sensu stricto, supporting the classification of both in the Naviculaceae. Haploid parthenogenesis and polyploid auxospores were found, lending support to the view that change in ploidy may be a significant mechanism in diatom evolution.     

ENDOCYTOSIS IN THE CROP OF THE SLUG, DEROCERAS RETICULATUM (MULLER) AND THE EFFECTS OF THE INGESTED MOLLUSCICIDES, METALDEHYDE AND METHIOCARB

Utilising the markers horseradish peroxidase (HRP) and lanthanumnitrate, uptake of endogenous material was demonstrated in thecrop of the slug, Deroceras reticulatum. Pinocytosis of HRPwas observed to occur rapidly, (within 5 min post feeding) inspecimens that had previously been starved for 48 h. Similarrates of uptake were recorded for lanthanum but this markerwas confined to a paracellular route. The effects of the molluscicidesmetaldehyde and methiocarb, following ingestion were studiedat the electron microscope level. At sub-lethal doses morphologicaldamage to the surface epithelium of the crop was attributableto both active ingredients. In addition the appearance of intracellularvacuoles within crop cells was evident from 24 h post treatmentwith methiocarb. (Received 7 February 1990; accepted 4 April 1990)     

ECOLOGY AND EVOLUTION OF MATING SYSTEMS OF FIDDLER CRABS (GENUS UCA)

1. General accounts of the natural history and behaviour of fiddler crabs suggest there exist two broad mating patterns in the genus. Most western and Indo-Pacific species mate on the surface of intertidal substrates near burrows females defend. The sexes associate only briefly during courtship and mating. In contrast, males of many American species court from and defend burrows to which females come for mating. Copulation occurs underground in burrows plugged at the surface; the sexes usually remain together for at least several hours. Here we summarize and contrast recent detailed field studies of the mating systems of U. pugilator, an American species, and U. vocans, a species widely distributed in the western and Indo-Pacific. We indicate how differences in the breeding ecology of these two species may account for basic differences in modes of sexual selection leading to the two broad mating patterns in the genus. 2. U. pugilator burrows in protected sandy substrates in the upper intertidal and supratidal zone. During ebb tide, nonbreeding crabs leave burrows they occupy during high tide to forage on food-rich substrates in the lower intertidal zone. Reproductively active males remain in the burrow zone where they fight for and defend burrows from which they court. Large males win most fights for burrows and tend to defend burrows high on the elevation gradient, especially during periods with relatively high tides. Females usually approach and descend the burrows of several males before choosing their mates by remaining in males' burrows. Males remain underground with their mates for 1–3 days until after they oviposit their eggs. Some males then emerge and leave their burrows while others sequester their mates in the chambers where mating and oviposition has occurred, dig new chambers and resume courtship, perhaps attracting additional females. In either case, females remain underground for approximately 2 weeks, finally emerging to release their planktonic larvae. Burrows that do not collapse due to tidal inundation or flooding by groundwater are best for breeding and usually are located relatively high on the elevation gradient. Females choose mates indirectly by preferring to breed in burrows that will remain intact while they oviposit and incubate their eggs. Large males mate more often than small males because they are better able to defend burrows at locations females prefer to breed. The mating system of U. pugilator may be classified as resource-defence polygyny. 3. U. vocans burrows in open muddy substrates in the mid- to lower intertidal zone. At a site near Chunda Bay, Australia, where the reproductive behaviour of this species has been studied in depth, both sexes feed near burrows they defend. Females tend to occupy their burrows for longer periods and move shorter distances than do males. Mating occurs on the surface near the burrows that females defend. Females accept both resident and wandering males as mates. They show no preference for mating with larger males. Female choice may be based on other male morphological or behavioural characteristics. Females oviposit their eggs either while on the surface or in their burrows. They produce relatively small clutches and are active on the surface throughout their breeding periods. Males fight both their neighbours and wandering males. Large males tend to win fights and defend burrows in areas where large females, which produce relatively many eggs, are most dense. Such areas may offer greater protection from predators than areas occupied by smaller females. Small males mate about as often as large males but may father fewer larvae. The mating system of U. vocans is resource-free and promiscuous. 4. The mating systems of U. pugilator and U. vocans differ fundamentally in that female U. pugilator require access to a specific microenvironment to breed successfully, while female U. vocans do not. We suggest this difference occurs because of contrasts in clutch sizes and the mobility and movement patterns of feeding females. Female U. pugilator produce relatively large clutches and probably experience more intense selection from factors that can cause egg loss and mortality than do U. oocans, which produce clutches of sufficiently small volume to be protected by their abdominal flaps. Hence, the range of suitable breeding environments for U. pugilator is small compared to that for U. vocans. In addition, U. pugilator burrows in areas that are relatively food-poor, leading to daily migrations to and from food-rich substrates in the lower intertidal zone, preventing female defence of an area suitable for both breeding and feeding. U. vocans, however, burrows in areas sufficiently rich to support feeding, leading to relatively low female mobility and defence of burrows that are also suitable breeding sites. 5. Adaptive radiation of the genus Uca in the Americas is manifest by trends toward smaller adult size, higher population densities, more frequent microgeographic sympatry and increased terrestriality, compared to species in the western and Indo-Pacific regions. We outline the general features of the selection mechanisms tying each of these trends to the evolution of resource—defence mating systems. Intraspecific variation in the courtship behaviour and site of mating in U. lactea and U. vocans supports our contention that resourse—defence behaviour tends to occur at high population densities. Additional data are needed to evaluate the other hypotheses critically.