The reproductive response of the protobranch bivalve Yoldia hyperborea to an intermittent influx of phytodetritus. An experimental approach

Yoldia hyperborea (Loven) is a deposit feeder species living in muddy sediments of Conception Bay (Newfoundland, Canada) where it is exposed to a seasonal input of sinking phytoplankton during spring. Data field indicates that this species exhibits an increasing gonad development shortly after the sinking of phytodetritus event, suggesting a close relationship between this food pulse and reproduction. Laboratory experiments carried out with a mixture of laboratory-grown senescent algae Isochrysis galbana, Tetraselmis suecica and Chaetoceros affinis were able to mimic the reproductive response described for Yoldia individuals inhabiting Conception Bay.A dual marker experiment using ¹⁴C and ⁶⁸Ge radiolabelled Thalassiosira nordenskioldii demonstrated that Y. hyperborea fed on T. nordenskioldii and 14C was incorporated into the gonad tissue. Consequently experimental individuals periodically supplied with senescent algae concentrate produced more and larger oocytes than control individuals. These results would help to understand the influence of the sinking phytodetritus in the reproductive activity of Y. hyperborea at Conception Bay.     

Stimulation of sex pheromone production by proteinaceous extracts of the bursa copulatrix in the redbanded leafroller moth

Pheromone biosynthesis in the redbanded leafroller moth, Argyrotaenia velutinana, was stimulated by homogenates of the bursa copulatrix. Although pheromonotropic activity was also extractable from the ovary, the activity of pheromone biosynthesis activating neuropeptide (PBAN) or bursa extracts was not impaired in isolated abdomens by removal of the ovary. Response to the bursa extracts was dependent on the dose administered and the time of incubation. Amounts of pheromone present in adult females of different ages appeared to be correlated with the extractable amount of pheromonotropic activity from their bursa copulatrix. Decapitation did not result in the suppression of burse factor production. Homogenates of the bursa elicited similar effects in both isolated gland and isolated abdomen incubations, but the brain neuropeptide, PBAN, was less active in the former than in the latter. Bursa extracts stimulated pheromone production in isolated abdomen incubations deprived of the bursa copulatrix, but PBAN did not. Loss of activity of bursa homogenates after treatment with either pronase E or carboxypeptidase Y indicated that the pheromonotropic factor is a proteinaceous substance. The mechanism through which pheromone production is regulated in redbanded leafroller moths is discussed. © 1992 Wiley-Liss, Inc.     

Functional morphology of the copulatory organs of a reed beetle and a shining leaf beetle (Coleoptera: Chrysomelidae: Donaciinae,Criocerinae) using X-ray micro-computed tomography

For more than 100 years it has been known that the sclerotised median lobe of beetles harbours a membranous structure (the "internal sac" or "endophallus") which is everted during copula inside the female genital tract. In order to explore the functional role of this structure and those associated with it, we cryofixed copulating pairs of Donacia semicuprea and Lilioceris lilii and studied the relative position of the elements of the copulatory apparatus of males and females by micro-computer-tomography.We found that the everted endophallus fills the lumen of the bursa copulatrix completely. Our data suggest that in Lilioceris lilii the tip of the sclerotised distal part of the ejaculatory duct, the flagellum, is positioned exactly over the opening of the spermathecal duct inside the bursa copulatrix. The mouth of the bursa copulatrix in Donacia semicuprea is armed with a strong muscle ring, and the whole wall of the bursa is covered externally with a layer of muscle fibres. These morphological differences correspond with differences in mating behaviour: In reed beetles (Donaciinae), females seemingly can control mating to a higher degree than in lily beetles (Lilioceris spp.).     

Reproduction of the Atlantic bobtail squid Sepiola atlantica (Cephalopoda: Sepiolidae) in northwest Spain

Atlantic bobtail squid (Sepiola atlantica) in northwest Spain show seasonal variation in population structure, with juvenile abundance peaking during summer and autumn. However, whether similar patterns exist for reproduction is unknown. Therefore, we describe the reproductive biology of 505 specimens of S. atlantica collected monthly during two consecutive years at two different sites off of Areamilla beach in the Ría de Vigo. Mature males displayed a type of sexual dimorphism previously unknown in members of this species, developing a muscular nodule in the base of each of the ventral arms over ontogeny. Reproductive output of both sexes was similar to that of other bobtail squids. Relative oocyte size (~10% mantle length) appeared to be similar to those of other bobtail squids. Females did not show evidence of having mated before complete maturity. Females of S. atlantica have group‐synchronous ovary maturation, with a positive correlation between female mantle length and ripe oocyte mass, suggesting a terminal investment strategy. Atlantic bobtail squids displayed the same seasonal patterns of reproductive traits at both sampling sites, with significant differences in reproductive activity between males and females. We consider reproductive traits in these small animals as adaptations to the coastal shelf lifestyle.     

Breeding and recruitment in a population of the New Zealand starfish Stichaster australis (Verrill)

The annual reproductive cycle of the New Zealand starfish Stichaster australis (Verrill) was determined at Maori Bay on the west coast of Auckland. S. australis has a clearly defined summer breeding season, closely repeated from year to year. Changes in the gonad shown by histological sections confirmed this cycle.S. australis juveniles reared in the laboratory were maintained on Mesophyllum insigne (Foslie) Adey substrata and the growth rates and feeding behaviour of individual starfish were determined. Settlement on the shore was from May to July each year. When the time of spawning is considered this implies a planktotrophic larval life of ≈ 6 months. This is considerably longer than laboratory studies on larval development would suggest.Growth of yearly settlement cohorts on a nursery site on the shore used in conjunction with laboratory results gave a fairly clear picture of growth after settlement. Growth rates followed a typical sigmoid curve, growth being slow initially and becoming more rapid later. The numbers of juveniles recruited to nursery areas vary from year to year but mortality following settlement appears to be low. It was found that juvenile Stichaster australis graze Mesophyllum insigne exclusively until they reach ≈ 0.8 cm in diameter (7–8 months old) when they may occasionally predate juvenile Perna canaliculus (Gmelin). The incidence of carnivorous feeding gradually increases until juveniles are ≈ 2.0–2.5 cm in diameter (15–18 months old) by which time they are exclusively carnivorous on small P. canaliculus. As growth continues juvenile starfish gradually migrate from nursery areas to adjacent reefs where there are dense beds of adult P. canaliculus. Starfish of this species become sexually mature when they reach ≈ 5–8 cm in diameter.     

Spawning strategy in Atlantic bobtail squid <Emphasis Type="Italic">Sepiola atlantica</Emphasis> (Cephalopoda: Sepiolidae)

This study aimed to determine the spawning strategy in the Atlantic bobtail squid Sepiola atlantica, in order to add new information to the knowledge of its reproductive strategy. A total of 12 females that spawned in aquaria were examined. Characteristics of the reproductive traits and egg clutches were similar to those of other known Sepiolidae. Clutch size varied from 31 up to 115 eggs. Females of this species had incorporated up to 1.58 times of their body weight into laid eggs. The size of laid eggs showed a positive correlation with maternal body size, supporting the idea that female size is a determinant of egg size. Our data suggest that S. atlantica is an intermittent terminal spawner, and that its spawning strategy comprises group-synchronous ovary maturation, multiple egg laying, and deposition of egg clutches in different locations. The obtained data provide insights for future comparative studies on reproductive allocation.     

Functional morphology of the sperm-containing chambers of the sea slug Okenia polycerelloides in the context of sexual selection

Sea slugs are interesting models to study post-copulatory sexual selection in simultaneous hermaphrodites due to the enormous variation of their reproductive systems. However, the knowledge of the functional morphology of their reproductive system is limited to few species, and it is rarely discussed in the context of sexual selection theory. In this study, we investigated the functional morphology of the sperm-containing chambers (i.e., ampulla, seminal receptacle, and bursa copulatrix) of the reproductive system of Okenia polycerelloides (Ortea & Bouchet, 1983), based on light, confocal, and electron microscopy. Although the morphology of the ampulla is similar to other species, indicating that it is a site for autosperm storage, we found some sperm facing the ampullar epithelium, a feature commonly regarded as characteristic of the seminal receptacle of sea slugs. The seminal receptacle of O. polycerelloides showed secretory activity and contained sperm with distribution and orientation suggestive of stratification of allosperm from distinct mating events, a feature that would affect sperm competition. The bursa copulatrix had epithelial cells with secretory and absorptive characteristics, and contained degraded sperm and yolk granules within its lumen. Comparative analyses of the contents of each organ demonstrated that sperm digestion occurs in the bursa copulatrix and affects sperm heads first, changing their morphology from slender and curved to shorter and ellipsoid before complete lysis. Although digestion and absorption of surplus sperm are currently the main hypothesized functions for the bursa copulatrix, its role in cryptic female choice should not be ruled out. The close structural connection between the seminal receptacle and bursa copulatrix, as well as their muscular walls, would enable control over the fate of the sperm received in each mating event, that is, storage or digestion.     

Acclimation to temperature in Actinia equina L.: Effects of season and shore level on aquatic oxygen consumption

Effect of seasonal and experimental acclimation to temperature upon aquatic oxygen consumption of the sea anemone Actinia equina L. has been studied in animals from two shore levels during the summer of 1981 and the winter of 1982. A clear influence of both season and shore level on the weight exponent is registered, higher values occurring during the summer. Seasonally acclimated animals from the upper shore showed perfect winter-summer compensation with lateral translation to the right of the R-T curve in response to warm acclimation while this pattern was coupled with clockwise rotation and partial compensation in specimens collected from the low shore. Experimental acclimation during the summer resulted in partial compensation at T_a 15°C and no acclimation was found at T_a 25°C; during the winter, only high shore specimens exhibited compensatory responses. A significant increase in oxygen consumption, regardless of shore level, occurs in winter in both seasonally and experimentally acclimated animals.     

Sclerotised spines in the female bursa associated with male’s spermatophore production in cantharidin-producing false blister beetles

Cantharidin is a defence chemical synthesised in only two beetle families Meloidae and Oedemeridae. In Meloidae, cantharidin is used as a defence chemical in eggs. However, in Oedemeridae the function of cantharidin remains unclear. Based on morphological comparison of female internal reproductive organs in 39 species of Oedemeridae, we found that some species have sclerotised spines in the bursa copulatrix (bursal spines), while others have no such spines. Molecular phylogenetic trees inferred from mitochondrial 16S and nuclear 28S rRNA gene sequences suggested multiple evolutionary origins of bursal spines from an ancestor without spines. In the species which lacked spines, males transferred small amounts of ejaculates to females; however, in species with spines, males transferred large spermatophores. Deposited spermatophores gradually disappeared in the bursa, probably owing to absorption. To compare the amounts of cantharidin in eggs laid by species with and without bursal spines, we constructed a new bioassay system using the small beetle Mecynotarsus tenuipes from the family Anthicidae. M. tenuipes individuals were attracted to droplets of cantharidin/acetone solution, and the level of attraction increased with cantharidin concentration. This bioassay demonstrated that the eggs of Nacerdes caudata and N. katoi, both of which species have conspicuous bursal spines, contain more cantharidin than the eggs of N. waterhousei, which lacks spines. In the former species, males transfer large spermatophores to the female, and spermatophores are eventually broken down and digested within the female’s spiny bursa. Thus, females with bursal spines may be able to provide more cantharidin to their eggs.     

Funktionsmorphologische Untersuchungen am männlichen Kopulationsapparat von Pelodera strongyloides (Schneider, 1866) (Nematoda,Rhabditidae)

Zusammenfassung Es wird die Feinstruktur des männlichen Kopulationsapparates bei Pelodera strongyloides beschrieben. Dieser besteht aus dem Spiculum, der Spiculumtasche und der Bursa copulatrix. Der gesamte Kopulationsapparat besitzt Papillen mit sensorischen Funktionen. Dabei handelt es sich bei den Papillen der Bursa um Chemorezeptoren, während die Papillen der Spiculumtasche und des Spiculums Mechanorezeptoren sein dürften. Ein Zusammenwirken aller Strukturen bei der Kopulation wird diskutiert.

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Structure and function of the male copulatory apparatus of Pelodera strongyloides schneider 1866 (Nematoda, Rhabditidae)

Summary The male copulatory apparatus of Pelodera strongyloides is described using electron microscopical pictures. The genital structures are composed of a spicule, a spicule sac and a bursa copulatrix. Papillae of the bursa copulatrix, which are chemoreceptors, and papillae of the spicule sac and the spicule, which are mechanoreceptors, represent the sensory equipment. The co-operation of all structures during copulation is discussed.

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Mit freundlicher Unterstützung der DFG (Se 162/11).     

A technique to artificially inseminate leafcutter ants

Artificial insemination (AI), the instrumental transfer of semen from the male to female reproductive organs, offers excellent opportunities to study mating system adaptations as it allows paternity to be experimentally manipulated. AI techniques have been developed for many animals, but rarely for ants, where they would be particularly useful as most species do not mate under controlled lab conditions. Here, we describe an AI technique for Atta leafcutter ants involving (1) the collection of ejaculates via induction of natural ejaculation, (2) storage in glass capillaries, and (3) transfer to queens using a modified AI equipment as used for honeybees. Queens were fixed and anesthetized in a queen holder, after which the sting chamber was opened with two steel hooks, the tip of the semen-containing glass capillary was inserted into the bursa copulatrix and the semen slowly expelled. Sperm was successfully stored in the spermatheca of queens, and some queens produced a small colony as a result. We could furthermore confirm the earlier observations that Atta semen is directly transferred to the spermatheca rather than to the bursa copulatrix as in most other eusocial insects. The technique that we present here can offer novel opportunities to study mating events such as sperm transfer, sperm competition, and cryptic female choice in ants. At present, the number of queens that produce colonies after AI remains low. However, this number will likely increase, as our results indicate that rearing conditions after AI influence colony founding success of artificially inseminated Atta queens.     

Regulation of reproductive behaviour and egg maturation in the tobacco hawk moth, Manduca sexta

ABSTRACT. The virgin female tobacco hawk moth, Manduca sexta, flies during the early scotophase in an LD 16:8 cycle at 24C then begins 'calling' within 2h. Mating lasts 3–4 h. Oviposition occurs in the succeeding scotophases if a tobacco plant is present. The switch from virgin 'calling' behaviour to mated ovipositional behaviour is mediated by the presence of sperm and/or associated testicular fluids in the bursa copulatrix. The corpora allata, which are necessary for egg maturation in this species, are activated via the NCC I and II around the time of eclosion. Feeding increases the activity of the corpora allata in the virgin female (as judged by the number of eggs matured in 4 days) but mating brings about a further stimulation of the activity of the corpora allata. The stretching of the bursa copulatrix by the insertion of the spermatophore during mating is probably the trigger for this response. Continued neural input from the bursa copulatrix to the brain is necessary to maintain the increased activity of the corpora allata.     

Mating behavior and genitalic counterparts in tiger beetles (Carabidae: Cicindelinae)

Comparative studies on the structure of genitalia in Pseudoxychila tarsalis Bates and the copulating behavior in 5 species of Cicindela respectively complement similar findings by Freitag [1] on Cicindela spp. and Palmer [4] on P. tarsalis. These strengthen the hypothesis that in tiger beetles the flagellum fits into the spermatheca duct during copulation; that the main function of the flagellum, which is closed at the apex and not connected to the ejaculatory duct, is to open and prepare the lumen of the spermatheca duct for sperm movement from the bursa copulatrix to the spermatheca; and that copulation proceeds in 3 phases: phase 1 in which the lumen of the spermatheca duct is cleared by the flagellum, phase 2 in which the flagellum is withdrawn from the spermatheca duct, and phase 3 in which semen is transferred from the gonopore of the ejaculatory duct to the bursa copulatrix, usually with a spermatophore.     

Genetic relationships among Pistacia species studied by SAMPL markers

Pistachio is economically important in Iran. Selection of suitable rootstocks, resistant to unfavorable and soil conditions and diseases, is important for increasing yield and the acreage of this crop. It is essential to identify the genetic relationships among Pistacia species for the breeding of pistachio rootstocks. The goal of this study was to determine the genetic relationship among Pistacia species (P. vera L., P. khinjuk Stocks., P. eurycarpa Yalt., P. atlantica subsp. atlantica Zoh., P. atlantica subsp. mutica Fish et C.A. Mey and P. atlantica subsp. cabulica Stocks.) with potential in the breeding of rootstocks using the selective amplification of microsatellite polymorphic loci (SAMPL) technique. Six primer combinations produced a total of 182 bands, with an average of 30.33 bands per primer pair, of which 128 were polymorphic. Three branches were obtained, the first containing P. vera, and the second containing P. khinjuk, P. eurycarpa, P. atlantica and subspecies mutica and cabulica, with numerous leaflets clustered in the third branch. UPGMA analysis separated P. atlantica subspecies from P. eurycarpa.     

Causes of sulfur isotope variability in the seagrass, Zostera capricorni

Sulfur has been proposed as a useful element to employ in addition to carbon and nitrogen in stable isotope studies of marine food webs, but variability in δ³⁴S of primary producers may prevent food web resolution. δ³⁴S values in green leaves of the seagrass, Zostera capricorni, showed considerable variability (12.7-17.6‰) in a survey in Moreton Bay, Australia. We demonstrated that δ³⁴S values were correlated with sediment organic matter (OM) content and height of seagrass on the tidal gradient, but these relationships were opposite to those expected from work elsewhere. In our survey, δ³⁴S values were relatively depleted at sites higher on the shore and with lower OM content. We did find the expected relationship of depleted δ³⁴S values where sediment porewater sulfide concentrations were higher. Any influence of OM content on δ³⁴S values would have been confounded in the survey by the relationship between height on shore and OM content itself. We separated the effects of height and OM content by creating the following treatments at one height on the shore: (1) OM added, (2) procedural control, and (3) untouched control. δ³⁴S values of seagrass in OM added plots were significantly depleted (5.6‰) relative to procedural (10.1‰) and untouched (11.0‰) controls 8 weeks after the manipulation. This demonstrated that OM content on its own does have the expected effect on δ³⁴S values of seagrass, so in the initial survey another factor, probably related to height on shore, must have overridden the influence of OM content. Seagrass roots are able to exude excess oxygen produced during photosynthesis, reoxidising sulfides in surrounding porewater. We demonstrated that the above and below-ground biomass of seagrass was higher low on the shore, and contend that higher seagrass productivity low on the shore results in greater reoxidation of sulfides and leads to more enriched δ³⁴S values of seagrass.     

Multidecadal variability in Atlas cedar growth in Northwest Africa during the last 850 years: Implications for dieback and conservation of an endangered species

Widespread forest dieback is a phenomenon of global concern that requires an improved understanding of the relationship between tree growth and climate to support conservation efforts. One priority for conservation is the Atlas cedar (Cedrus atlantica), an endangered species exhibiting dieback throughout its North African range. In this study, we evaluate the long-term context for recent dieback and develop a projection of future C. atlantica growth by exploring the periodic variability of its growth through time. First, we present a new C. atlantica tree-ring chronology (1150–2013 CE) from the Middle Atlas mountains, Morocco. We then compare the new chronology to existing C. atlantica chronologies in Morocco and use principal components analysis (PCA) to isolate the common periodic signal from the seven longest available records (PCA₇, 1271–1984 CE) in the Middle and High Atlas portions of the C. atlantica range. PCA₇ captures 55.7% of the variance and contains significant multidecadal (˜95 yr, ˜57 yr, ˜21 yr) periodic components, revealed through spectral and wavelet analyses. Parallel analyses of historical climate data (1901–2016 CE) suggests that the multidecadal growth signal originates primarily in growing season (spring and summer) precipitation variability, compounded by slow-changing components of summer and winter temperatures. Finally, we model the long-term growth patterns between 1271–1984 CE using a small number (three to four) of harmonic components, illustrating that suppressed growth since the 1970s – a factor implicated in the dieback of this species – is consistent with recurrent climatically-driven growth declines. Forward projection of this model suggests two climatically-favourable periods for growth in the 21st century that may enhance current conservation actions for the long-term survival of the C. atlantica in the Middle and High Atlas mountains.     

Spermatophore expulsion in the carrion beetle Silpha perforata (Coleoptera: Silphidae)

Silphinae (Coleoptera: Silphidae) is an abundant decomposer that plays important roles in the ecosystem. However, there is little information about the life history of this taxon. We found sperm displacement behavior in carrion beetle Silpha perforata. Copulating males bit the female's antenna strongly and inserted the penis into the partner's genital organ more than once. We found a white substance on the tip of penis during copulation. We examined whether this white substance is a previous male's spermatophore, which was removed from the mating partner. When females were dissected just after mating, the same substance that often presents on the penis of mating males was found in the bursa copulatrix of females, although the bursa copulatrix of virgin females was empty. Male behavior during copulation with females of different mating history was also observed to confirm that the removal of spermatophores was observed only in copulation with females that have the spermatophores of previous males. Consequently, we estimated that S. perforata males removed spermatophores of previous males from mating partners. In addition, we dissected the males frozen during copulation, and inspected the penis morphology. This observation revealed that the apical part of the penis was usually hidden in the basal part of penis, but expanded and appeared during insertion. This apical part had many spines, which play an important role in sperm displacement and sexual conflict in some species. These results indicate that there is the sperm competition in S. perforata. This is the first report on sperm competition in Silphinae.     

Symbiotic state influences life-history strategy of a clonal cnidarian

Along the North American Pacific coast, the common intertidal sea anemone Anthopleura elegantissima engages in facultative, flexible symbioses with Symbiodinium muscatinei (a dinoflagellate) and Elliptochloris marina (a chlorophyte). Determining how symbiotic state affects host fitness is essential to understanding the ecological significance of engaging in such flexible relationships with diverse symbionts. Fitness consequences of hosting S. muscatinei, E. marina or negligible numbers of either symbiont (aposymbiosis) were investigated by measuring growth, cloning by fission and gonad development after 8.5–11 months of sustained exposure to high, moderate or low irradiance under seasonal environmental conditions. Both symbiotic state and irradiance affected host fitness, leading to divergent life-history strategies. Moderate and high irradiances led to a greater level of gonad development in individuals hosting E. marina, while high irradiance and high summer temperature promoted cloning in individuals hosting S. muscatinei and reduced fitness of aposymbiotic anemones. Associating with S. muscatinei may contribute to the success of A. elegantissima as a spatial competitor on the high shore: (i) by offsetting the costs of living under high temperature and irradiance conditions, and (ii) by promoting a high fission rate and clonal expansion. Our results suggest that basic life-history characteristics of a clonal cnidarian can be affected by the identity of the endosymbionts it hosts.     

Catoptinae subfam. n., a new subfamily of carpenter-moths (Lepidoptera,Cossidae)

The new subfamily of Cossidae; Catoptinae Yakovlev, subfam. n., well distinguished from other representatives of the family, is described. The new subfamily includes two genera: Catopta Staudinger, 1899 (type genus) and Chiangmaiana Kemal et Koçak, 2006. A catalogue of the subfamily is presented. One new synonym Catopta hyrcanus (Christoph, 1888) = Catopta brandti Bryk, 1947, syn. n., is established. The new subfamily has the following distinguishing features: short valvae; reduced processes of transtilla; vesica with numerous cornuti; pearshaped bursa copulatrix; and very short ductus bursae.