吴氏角叶蚤幼虫形态记述及其与同属另外三种的比较（蚤目：角叶蚤科）

描述了吴氏角叶蚤Ceratophyllus wui Wang et Liu 的幼虫形态,并与同属三种蚤幼虫作比较,标本采自湖北省西北部神农架海拔2 300 m 短嘴金丝燕四川亚种 Collocalia brevirostris innominata巢窝内。     

Dispersal and prepupation behavior of Chilean sympatric Drosophila species that breed in the same site in nature

We investigated dispersal patterns of Drosophila larvae searchingfor pupation sites over three substrates to determine the roleof spatial heterogeneity and presence of other species on prepupationbehavior. We used D. melanogaster, D. hydei, and D. pavani whoseparents emerged from apples collected in one orchard. Each speciesshowed different preferences for substrates on which to pupate,particularly in the presence of another Drosophila species.Larval locomotion rate and turning behavior in D. melanogaster,D. hydei, and D. pavani were modified depending this upon thetype of substrate (agar and sand) on which the larvae crawled.These two behaviors are involved in dispersal and aggregationof pupae. Distance between pupae of the same species decreaseswhen larvae of another species pupate on the same substrate.Aggregated distributions over the substrates lead to patcheswith few or no individuals. These could serve as pupation sitesfor other Drosophila species that, in nature, also emerge fromsmall breeding sites.     

马尾松毛虫对马尾松和湿地松的选择与适应研究

用马尾松老叶、新叶,湿地松老叶、新叶,当年生马尾松新叶、湿地松新叶和当年生以20％和40％β-蒎烯处理过的马尾松新叶作食料饲养马尾松毛虫。结果表明：马尾松毛虫幼虫在第1代发生期取食马尾松老叶、马尾松新叶、湿地松老叶和湿地松新叶等4种不同质量的食料后,因其食料中10种必需氨基酸含量和挥发性物质β-蒎烯含量的不同,导致幼虫的存活率差异显著。其中,取食马尾松老叶的幼虫成活率最高（44％）,依次为马尾松新叶（32.7％）、湿地松老叶（4％）,而取食湿地松新叶的幼虫全部死亡。通过马尾松针叶增加外援β-蒎烯喂养马尾松毛虫实验,表明增加了外源β-蒎烯的松针饲养的马尾松毛虫幼虫与用同样松针未增加外源β-蒎烯饲养的幼虫相比,死亡率明显提高;松树中β-蒎烯含量的增加与幼虫成活率呈显著负相关。由此,我们阐明了马尾松与湿地松对马尾松毛虫的抗虫机制。     

Distribution, Taxonomy, and Boring Patterns of Marine Endolithic Algae

Penetration of calcareous substrates by algae involves differentmicroenvironments. Endolithic algae include two different lifeforms: (1) algae colonizing existing spaces within the rock,and (2) algae actively boring within the carbonate substrate. Two species of boring Cyanophyta were studied, and their boringswere compared in exposed calcite (Island spar). The size andpattern of borings reflect the corresponding properties of thealgae and show taxonomic distinctions. The direction of thetunnels and their wall sculptureare determined by the planesof crystal cleavage and twinning. Algal boring is a dissolution process performed by the terminalcells of endolithic filaments. The space dissolved away by analga has the shape of a miniature calcite crystal. Dissolutionproceeds along the crystal twinning lines diagonally to theprevious microcrystal space. Thetunnel represents a sequenceof such microcrystal-shaped spaces. Both biological and mineralogicaldeterminants should be considered in the interpretation of algalboring patterns.     

Mechanics and Ecological Role of Swimming Behavior in the Caddisfly Larvae <Emphasis Type="Italic">Triaenodes tardus</Emphasis>

Caddisfly larvae are typically restricted to benthic microhabitats due to the presence of mobile tubular cases constructed out of mineral or organic material. Members of one family (Leptoceridae) use setae on extended metathoracic legs to swim. We describe the swimming behavior of a North American caddisfly, Triaenodes tardus, and experimentally evaluate two hypotheses proposed to explain this behavior. Triaenodes swam 1.47 cm/s, while carrying almost twice their mass in the case material. The larvae employ a stereotypic sequence of motions that likely reduce resistance during the upstroke and increases forward momentum during the downstroke. When placed on substrates of different sizes, larvae swam more on fine sediments but did not elevate off the sediment. After larvae were provided with living or artificial vegetation, the number of swimming bouts decreased compared to a pre-treatment observation period. These results indicate swimming likely does not function to facilitate movement off fine sediments, but rather, helps larvae locate and move between aquatic macrophytes which are the primary habitat of this, and other, swimming species.     

Comparative Ultrastructure and Organization of the Prismatic Region of Two Bivalves and its Possible Relation to the Chemical Mechanism of Boring

The prismatic region of two bivalve molluscs exemplifies, inits structure and organization, one of the types of differentiatedcalcareous substrates through which boring organisms must penetrate. The oriented inorganic crystals, separated from one anotherby intercrystalline "spaces", are structurally organized intowell defined prisms. The prisms of each bivalve vary in shapeand size and are delineated from one another by electron-lucent,non-calcified regions. The demineralized organic matrix is also structurally organizedinto prisms, delineated from one another by prism sheaths, andan intraprismatic matrix structurally organized into closelypacked sheet-like compartments and subcompartments in whichthe inorganic crystals are deposited. The non-mineralized intercrystalline "spaces" between the individualinorganic crystals of the same or adjacent rows in a mineralizedsection are occupied by the walls of the intraprismalic sheet-likecompartments. Similarly, the non-calcified electronlucent regionsdelineating one mineralized prism from the next are occupiedby the thick prism sheaths. These portions of the organic matrixwhich fail to mineralize completely undoubtedly provide readypathways for the passage of solutes and solvents through thesetissues of highly ordered, densely packed, inorganic crystals.Moreover, the framework of the organic matrix, which fails tomineralize in these heavily calcified, molluscan substrates,may provide the primary, not the secondary source of chemicalattack during boring, for once the sheaths and compartmentssurrounding the crystals are broken down or solubilized, thecrystals are themselves loosened and freed for mechanical removalby shell-penetrating organisms.     

小菜蛾烟碱型乙酰胆碱受体α亚基cDNA的克隆、序列分析与不同发育阶段表达分析

烟碱型乙酰胆碱受体(nAChR)介导昆虫中枢神经系统中胆碱能突触兴奋性神经递质的快速传递,也是新烟碱类杀虫剂和多杀菌素的作用靶标。本研究利用RT-PCR和RACE技术,克隆了小菜蛾Plutella xylostella nAChR α亚基的一个新基因(Pxα8)的全长cDNA(GenBank登录号为EU914853)。Pxα8的cDNA序列全长1 744 bp,开放阅读框为1 602 bp,编码534个氨基酸,具有nAChR α亚基的典型特征,与其他昆虫nAChR α8亚基具有77%～96%的相似性,与果蝇nAChR β2亚基具有76%的相似性。Pxα8的开放阅读框存在单核苷酸多态性位点,导致多个位点氨基酸的替换。雌性4龄幼虫的多态性位点多于雄性4龄幼虫,而且雌、雄4龄幼虫的多态性位点均不相同。半定量RT-PCR研究结果表明,Pxα8 mRNA在成虫期表达量高于蛹期和4龄幼虫期。本研究结果为进一步研究小菜蛾nAChR 亚基的多样性和对多杀菌素的靶标抗性机制提供重要基础。     

The zoeal stages and megalopa of Portunus rubromarginatus (Lanchester) (Decapoda: Portnnidae), reared in the laboratory

The present state of knowledge concerning Portunus larvae isreviewed, and the three zoeal and the megalopa stages of P.rubromarginatus are described and figured. Details of appendagesetation are tabulated. This species is unusual amongst knownPortunus spp. in having only three zoeal stages and, like otherPortunus spp. but in contrast with other Portuninae, it has4 + 4, or 4 + 1 + 4, setae on the posterior telson border. When compared with larvae of the five other Indo-West PacificPortunus species whose larvae are known P. rubromarginatus zoeaeare readily distinguished from all, except P. hastatoides, usingthe key features given by Kurata (1975). Comparison was madebetween first zoeae of these two species, and also of P. pelagicusand P. sanguinolentus, using larvae reared by the authors. Itwas found telson characters alone allow distinction betweenlarvae of these four species. These characters are tabulated. P. rubromarginatus megalopae differ from those known for congenitorsin having a large spine on the uchium of the first pereiopod,but not on the carpus, and in having relatively very small sternalcornuae. Several of these features disagree with those previously thoughtto characterise larval Portuninae or Portunus species.     

Phenotypic plasticity of larval retreat design in a net-spinning caddisfly

Larval Macrostemum carolina caddisflies construct silken catchnetswithin protective retreats, often on submerged trees and branches(i.e., snags). In the Savannah River, M. carolina larvae constructthree distinct retreats that differ in the configuration ofthe water entrance hole: (1) at the end of a silken tube, (2)flush with the top of the retreat, and (3) backed by a 180-degreesilken backstop. To identify the proximate mechanism mediatingthis retreat polymorphism, we removed larvae of known phenotypefrom their original retreats and brought them into the laboratory,allowing them to construct new retreats. We found that (1) larvaecan construct more than one type of retreat, so variation inthis behavior is not under strict genetic control; (2) larvaedo not preferentially reconstruct their original retreat design,so these alternative behaviors apparently exhibit little heritability;and (3) larvae primarily construct each phenotype in a particularmicrohabitat (i.e., "tube" and "backstop" retreats are principallyconstructed on the downstream half of the snag, and "flush"retreats on the upstream–bottom quadrant). Therefore,the retreat polymorphism in M. carolina is phenotypically plasticand is controlled by microhabitat location or a correlated environmentalvariable. Most net-spinning caddisflies construct their netsin fairly specific microhabitats. However, behavioral plasticityallows M. carolina larvae to construct retreats all around asnag, thereby reducing potentially intense competition for spacewith other net-spinning caddisflies. Consequently, this maybe the ultimate reason this polymorphism evolved.     

Predation by a carnivorous marine copepod, Euchaeta elongata Esterly, on eggs and larvae of the Pacific hake, Merluccius productus

The predatory behavior of the carnivorous marine copepod, adultfemale Euchaeta elongata Esterly, feeding on eggs and larvaeof the Pacific hake, Merluccius productus, was examined in thelaboratory and in a natural setting. E. elongata did not feedon eggs. Predation on larvae is believed to depend on larvalswimming behavior: (1) predation rates were low on early stageyolk-sac larvae which are inactive swimmers and are relativelyundetected by the predator; (2) rates were high on middle stageyolk-sac larvae which are more active swimmers yet have a poorlydeveloped escape response; and (3) rates were low on largerlarvae which are able to escape the predator effectively. Starvedhake larvae were more vulnerable to predation due to a poorescape ability although they were less active and not easilydetected. The presence of naturally occurring alternative prey,Pseudocalanus sp., depressed the rate of E. elongata predationon hake larvae. In an analysis of field data, hake larvae andE. elongata were found to occupy the same depths in Dabob Bay.A high percentage of E. elongata collected had apparently beenfeeding on hake larvae, as indicated by the presence of pigmentsin their guts. Survival of hake larvae in late spring appearsto be relatively poor compared with early spring; poorer survivalin late spring may be due partly to an increase in the abundanceof invertebrate predators, such as E. elongata. ^*Current address: Northwest and Alaska Fisheries Center, 2725Montlake Blvd, Seattle, WA 98112, USA.     

Morphological and Physiological Responses of Echinoderm Larvae to Nutritive Signals

SYNOPSIS. Echinoid larvae have been found previously to developshorter arms as phytoplankton concentrations increase. In thepresent study, the skeletal dimensions of larvae of the seaurchins Lytechinus pictus and Strongylocentrotus purpuratuswere measured after exposure to dissolved organic compoundsin seawater. The presence of glucose or individual amino acids(at 1 or 2 µM), a mixture of 16 different amino acids(100 nM each), or algal exudate resulted in larvae with shorterarms (by 12 to 88%), relative to larvae in seawater with noadditions. Larvae exposed to mixtures of amino acids also hadchanges in the constituents of their internal free amino acidpools (as determined by HPLC). For another echinoid, Dendrasterexcentricus, amino acid transport (T, from 500 nM) by individuallarvae (n = 47) scaled to arm length (L) as follows: T = 2.06L^0.81(0.81 ± 0.26,95% confidence intervals). Mass (M) andmetabolic rate (MR) did not scale in the same manner (as transport)to arm length for larvae of the echinoid Centrostephanus coronatus(MR = 148L^1.51; M = 1.7L^2.01). These characteristics may scaleto arm length independently from transport rate under certainconditions. Larvae of echinoderms respond morphologically to"signals" in their environment that may indicate the availabilityof dissolved and paniculate nutrients. This in turn will haveconsequences for their ability to take up and metabolize thesenutrients. The response may be mediated by surface receptorsfor dissolved organic compounds, or by changes in the sizesof intracellular substrate pools.     

Integumental organs of the phyllosoma larva of the rock lobster Jasus edwardsii (Hutton)

The external morphology and distribution of the integumentalorgans of the final-stage phyllosoma of the rock lobster Jasusedwardsii were examined. Seven types of organs were recognizedon the integument of the body trunk, antennules and antennae:plumose setae, simple setae, porous setae, aesthetasc setae,simple pores, dorsal cuticular organs and dome-shaped structures.The plumose setae and simple pores were abundant on the dorsalsurface of the cephalosome, abdomen and telson. The dorsal cuticularorgans were present only on the dorsal surface of the cephalosome,and the aesthetasc setae were restricted to the antennule. A comparison of the morphology of these organs with the senseorgans of other decapods with known function suggests that thedorsal surface of the body trunk is one of the major sites ofreception of near-field water movement in the Jasus phyllosoma.     

The urticating setae of Ochrogaster lunifer,an Australian processionary caterpillar of veterinary importance

The bag‐shelter moth, Ochrogaster lunifer Herrich‐Schaffer (Lepidoptera: Notodontidae), is associated with a condition called equine amnionitis and fetal loss (EAFL) on horse farms in Australia. Setal fragments from O. lunifer larvae have been identified in the placentas of experimentally aborted fetuses and their dams, and in clinical abortions. The gregarious larvae build silken nests in which large numbers cohabit over spring, summer and autumn. The final instars disperse to pupation sites in the ground where they overwinter. Field‐collected O. lunifer larvae, their nests and nearby soil were examined using light and electron microscopy to identify setae likely to cause EAFL and to determine where and how many were present. Microtrichia, barbed hairs and true setae were found on the exoskeletons of the larvae. True setae matching the majority of setal fragments described from equine tissue were found on third to eighth instar larvae or exuviae. The number of true setae increased with the age of the larva; eighth instars carried around 2.0–2.5 million true setae. The exuvia of the pre‐pupal instar was incorporated into the pupal chamber. The major sources of setae are likely to be nests, dispersing pre‐pupal larvae and their exuviae, and pupal chambers.     

"GIGANTISM" OF CHLORELLA VULGARIS I. MECHANISM OF INDUCTION OF CIGANTISM

1. Based on the microscopic observations, two stages, "giant cellstage" and the subsequent "palmelloid body stage", were distinguishedin the process of formation of giant Chlorella induced by theaddition of sugars. The "giant cell" is much larger in sizethan the control cell, but the other morphological featuresare the same as those of the latter. The "palmelloid body" isa form composed of many conjoined autospores.
2. When a highconcentration of glucose was maintained in the medium,gigantismwas also maintained. Under this condition, the algashows acyclic transformation between "giant cell" and "palmelloidbody"without returning to the small single cells.
3. Large amountsof carbohydrate composed of hexose were foundto be accumulatedin the giant algal cells, and it was inferredthat this carbohydrateaccumulation causes greater enlargementof cell volume as comparedwith control cells.
4. Uronic acids, which were found to be absentin the control cells,were formed and lost in the cells culturedin the glucose mediumin parallel with the appearance and disappearanceof gigantism.
5. Pectic substances, from which uronic acids areconsidered tobe derived during the extraction procedure, werefound to bepresent only in giant Chlorella.
6. The conjoinedautospores in giant Chlorella (at the palmelloidbody stage)were separated to some extent by the addition ofEDTA, and theresulting cells were similar to control Chlorellacells.
7. Basedon these results it was inferred that inductive formationofthe pectic substances is causally related with the appearanceof "palmelloid body".

¹ Present address: Department of Chemistry, College of GeneralEducation, Osaka University, Toyonaka, Osaka.     

Amino acid composition of autotrophic and heterotrophic cultures of the Emerson strain, of Chlorella

"Giant" cells of the Emerson strain of Chlorella are deficientin certain peptide amino acids as compared with normally growingcells. "Giant" cell peptides lack aspartic acid, glutamic acidand alanine (major peptide amino acids in dividing cells) althoughall three are present in "giant" cells as free amino acids andin the protein fraction. (Received October 18, 1975; )     

两近缘种烟草上棉铃虫种群适合度的比较研究

分别在室内和自然条件下,比较研究了普通烟草和黄花烟草两种不同寄主植物上棉铃虫生长发育、食物转化和利用及种群增长情况。结果表明： (1) 室内26±1℃、75%±5% RH和16L∶8D光周期条件下,与普通烟草相比,黄花烟草上幼虫的发育历期显著延长,1龄和2龄幼虫的存活率及雌蛾产卵量显著下降,种群净增殖率（R₀=30.5374）和内禀增长率（r_m=0.0951）减小;(2) 6龄幼虫对两种烟草的近似消化率及其相对生长率无显著差异,但对黄花烟草的利用率和转化率显著下降,相对取食量显著提高;(3) 第2代棉铃虫在普通烟田的种群增长（I=1.9922>1）比黄花烟田（I=1.1581>1）快,“烟草和其他”对种群起主要控制作用,特别是对低龄幼虫;第3代棉铃虫在普通烟田的种群增长有所减慢但仍呈上升趋势（I=1.5994>1）,而在黄花烟田则呈下降趋势（I=0.6434<1）,低龄幼虫受烟草抗性和雨水等的影响较大,高龄幼虫被病菌感染的数量增多。这些结果表明,与普通烟草相比,黄花烟草不适合棉铃虫种群的增长和繁殖。     

Capelin larvae (Mallotus villosus) and community structure of zooplankton off the coast of northern Norway

Capelin larvae (Mallotus villosus) and mesozooplankton werecollected in May 2001 in the southern part of the Barents Sea.During the period of hatching and first feeding, capelin larvaeexperience high mortality rates. In order to understand theunderlying mechanisms influencing larval survival, we monitoreda selected site for 10 days using a variety of different samplingapproaches. Hydrological parameters conductivity–temperature–depth–fluorescence(CTDF) were recorded and zooplankton samples obtained simultaneouslyusing MOCNESS at three time periods. The mesozooplankton consistedessentially of copepods (85), dominated by Calanus finmarchicus.The zooplankton community consisted of different assemblagesderived from different areas (i.e. different water masses; Atlanticand coastal). Capelin larvae were found in surficial coastalwaters. Copepod nauplii and C. finmarchicus were less abundantin coastal waters where small copepodites (such as Acartia spp.and Temora longicornis) were found together with early stagesof coastal invertebrates that are possible prey for capelinlarvae. We suggest that capelin larvae base their foraging onsmall prey organisms frequently found among the coastal zooplanktonand that these larvae are less dependent on the propagationof the recruiting generation of C. finmarchicus present fromApril to June.     

SCALE-WORMS--OCCASIONAL FOOD OF OCTOPUS

Harpoon-like setae from the polychaete scale-worm, Hermionehystrix, were found embedded deeply in the brain of Octopusvulgaris. The setae had passed across the cuticular lining andmuscles of the oesophagus before entering the surrounding softnervous tissues. Further investigation showed that Octopus willeat Hermione, confirming other reports that polychaetes formpart of the diet of octopods. (Received 23 November 1982;     

Ecological Aspects of Some Coral-Boring Gastropods and Bivalves of the Northwestern Red Sea

More than 17 molluscan species were obtained from burrows incoral substrata at Al-Ghardaga (Hurghada on maps) on the RedSea coast, six of which in particular bore into livingcolonies.The species reported in this paper belong to the families Mytilidae,Coralliophilidae, and Gastrochaenidae. The direction of boringin living corals is to the outside, the borers keeping pacewith the growing coral layer to maintain their burrows open.Coral growth is generally of a higher rate than that of borers,and burrows are accordingly mostly much larger than their inhabitants.There is evidence in such cases that burrows form initiallyby growth of coral around the settling young. Boring of Lithophagaspecies is mostly due to the abrasive action of the shell whichmoves straight and posteroventrally without any rotation. Incoralliophilids,boring is also executed mechanically by the turning movementsof the shell. Boring in dead coral is directed inwards, andburrows are nearly as large as the borers. The latter avoidthe blocking of their burrows (e.g., by a living coral incrustation)either by great siphonal extension (Rocellaria) or the freeends of the shell may be strengthened to maintain the capabilityof boring in the opposite direction (Lithophaga laevigata).Both L. luevigata and Modiola chmamomeus bore mainly mechanicallyby the rocking movements of the shell. Chemical boring is stilla possibility,particularly in the posterior narrow region ofburrows of Modiola lodging the extended pallial siphons whichare deprived of any effective mechanical devices for boring.Therole of boring algae in rarefying bored coral material hasalso to be included as an indirect chemical factor.     

Bioerosion experiments at Lizard Island,Great Barrier Reef

The rates at which dead coral substrates are modified by bioerosional processes were determined by exposing recently killed corals for up to four years in a variety of reef environments at Lizard Island (northern Great Barrier Reef). Grazers were the major croding agents of these coral substrates and exhibited differences between sites that varied between sampling periods. Subtidal reef slopes and lagoon environments of water depths < 20 m were subjected to higher average rates of grazing erosion (0.30–1.96 kg/m²/y) than shallow depths less than 1 m (0.07–0.26 kg/m²/y). A deep site at 20 m experienced low average rates of grazing (0.08–0.29 kg/m²/y). Boring rates by worms (polychaetes and sipunculans), sponges and molluscs were relatively low and varied between sites, but increased with length of sampling period as larger borers succeeded the initial colonizing small polychaete worms. We hypothesize from these experiments that the extent of boring in reef substrates will be influenced by the interaction between the succession of the boring community and the rate at which the substrate is destroyed by grazing. We suggest that the level of grazing modifies the successional pattern of borers by removing the surface substrate and continually exposing bare substrate that can be colonized by early boring colonists. Thus, constant high levels of grazing may maintain the boring community at an early successional stage and prevent the development of a mature boring community. In order to establish large borer populations, reef substrates must be protected from extensive grazing bioerosion. This interaction of grazing and boring has important implications for the way dead coral is preserved in different reef environments.