Feeding Colonies Research Articles

A severe sacbrood virus outbreak in a honeybee (Apis mellifera L.) colony: a case report

A honeybee colony, part of an apiary of nine, showed abnormalities in brood pattern and was thus presented for study. A classic veterinary medicine approach has allowed the diagnosis of a severe case of sacbrood virus (SBV) confirmed by a high viral load in affected larvae. SBV is known to infect larvae of the honeybee (Apis mellifera), resulting in failure to pupate and ultimately death of infected larvae. Several contributing factors combined, among them the parasite Varroa destructor, have been identified in this particular affected colony to explain the clinical outbreak of the disease whereas, in the majority of cases, infected colonies remain asymptomatic. As no specific cure of honeybee viruses is available, the management of these contributing factors is essential, including feeding of colonies and control of the Varroa parasite. After implementation of management solutions, the colony rapidly recovered in six weeks, but did not recommence honey production and remained at higher risk of a winter collapse. An earlier control management would have been more effective: regular visits of the colonies by the beekeepers should be the rule in order to detect abnormalities and also to detect and eliminate as early as possible the combination of factors that contribute to the proliferation of the virus.

A scientific note on the use of external feeders for the Amazonian stingless bee Melipona flavolineata (Apidae, Meliponini)

Artificial feeding of stingless bee colonies is widely applied in meliponiculture to maintain colonies in good conditions during periods of natural food scarcity. Traditionally, most stingless beekeepers tend to adopt the individual feeding of colonies, to avoid conflicts among colonies or competition with feral species. We trained foragers from Melipona flavolineata colonies to collective feeders containing sugar syrup, and showed they are useful for the management of this species, since they did not cause significant intra and interspecific conflicts, and thus, worker losses. Besides, most colonies from the meliponary frequented the feeder, showing that collective feeding in this species is possible and can be recommended to keep colonies in good condition during periods of natural food dearth or after honey harvesting.

Plant-derived differences in the composition of aphid honeydew and their effects on colonies of aphid-tending ants.

In plant–ant–hemipteran interactions, ants visit plants to consume the honeydew produced by phloem-feeding hemipterans. If genetically based differences in plant phloem chemistry change the chemical composition of hemipteran honeydew, then the plant's genetic constitution could have indirect effects on ants via the hemipterans. If such effects change ant behavior, they could feed back to affect the plant itself. We compared the chemical composition of honeydews produced by Aphis nerii aphid clones on two milkweed congeners, Asclepias curassavica and Asclepias incarnata, and we measured the responses of experimental Linepithema humile ant colonies to these honeydews. The compositions of secondary metabolites, sugars, and amino acids differed significantly in the honeydews from the two plant species. Ant colonies feeding on honeydew derived from A. incarnata recruited in higher numbers to artificial diet, maintained higher queen and worker dry weight, and sustained marginally more workers than ants feeding on honeydew derived from A. curassavica. Ants feeding on honeydew from A. incarnata were also more exploratory in behavioral assays than ants feeding from A. curassavica. Despite performing better when feeding on the A. incarnata honeydew, ant workers marginally preferred honeydew from A. curassavica to honeydew from A. incarnata when given a choice. Our results demonstrate that plant congeners can exert strong indirect effects on ant colonies by means of plant-species-specific differences in aphid honeydew chemistry. Moreover, these effects changed ant behavior and thus could feed back to affect plant performance in the field.

Plant–rhizobia interactions alter aphid honeydew composition

Both above- and below-ground interspecific interactions contribute to ecosystem functioning in terrestrial systems, and the integration of below- and above-ground interactions is crucial for deepening our knowledge of nutrient cycling and community dynamics in terrestrial ecosystems. The present study explored the effects of plant–microbe interactions on aphid honeydew quality and quantity and important factors mediating ant–aphid mutualisms and below-ground nutrient dynamics. Soybean aphids (Aphis glycines) were inoculated onto two closely related strains of soybean plants: a nodulating strain that associates with rhizobia and a non-nodulating strain that does not harbor any nitrogen-fixing bacteria. As expected, prior to aphid inoculation, nodulating plants were significantly taller and had more leaves than non-nodulating plants. Aphids feeding on nodulating strains were found to reach slightly larger colony sizes and produce honeydew with significantly different sugar profiles than those feeding on non-nodulating plants. The honeydew collected from aphid colonies feeding on nodulating plants contained 160 % more total sugars than honeydew collected from colonies feeding on non-nodulating plants, but there was no difference in total amino acid-N content in honeydew from colonies feeding on the different plant strains. We discuss the implications of honeydew composition for nutrient cycling and community dynamics and suggest areas of future research to elucidate the consequences of altered aphid honeydew composition on ecosystem properties.

Economic benefits of using prebiotic and probiotic products as supplements in stimulation feeds administered to bee colonies

Spring stimulation feeding of honeybee colonies (Apis mellifera carpatica) is a very important technique for the encouragement of productive foraging. In addition to improving bee health by creating favorable conditions for the development of a beneficial intestinal bacterial flora, the use of prebiotic and probiotic supplements in the feed promotes good colony development, thus increasing the forager population. This paper presents the results for the economic benefit measured following use of supplements with acidifying substances (acetic and lactic acids) and probiotic products (Enterobiotics and Enterolactis Plus), as well as the synergism between them. A total of 110 bee colonies were studied, being fed with sugar syrup (1.4 L/colony weekly) between 25 March and 15 April, supplemented according to a controlled schedule. On 20 April the bees were transferred to a rapeseed field for foraging, and then at the beginning of May they were transferred elsewhere for acacia foraging. Honey production was measured for each experimental variant after each foraging period. Colonies fed with sugar syrup containing prebiotic and probiotic supplements registered higher honey production levels and showed a higher profit (ranging from +14.67% to +45.49%) in comparison with the control group.

INFLUENCE OF SOME POLLEN SUBSTITUTES ON BROOD REARING OF HONEY BEE AND WORKERS LONGEVITY

The present study was performed in a private apiary at Ayash village, El-Mehalla EL-Kobra, GharbiaGov. during the dearth season from January up-to March, 2011. Three protein diets were used as pollen substitutes for honey bees, Apismellifera, feeding i.e. soybean flourmaizeflour and wheat flour (alternative protein diets), Also sucrose solution (sugar syrup;) (2 : 1 w/w) was added. All the cages were fed on the mentioned diets for 12 weeks.Results indicated that, significant differences were found between treatment groups in sealed brood rearing workers produced by colonies during the study period when compared with the control treatment. Colonies feeding on soybean flour showed the increase in the mean of brood rearing by 75.30 inch2 followed by wheat flour (51.00 inch2) then maize flour (35.30 inch2) comparing with the control treatment (20.30 inch2). Soybean occupied the first rank in the consumption rate (48.46 gm /10 days) followed by 30.00 gm/10 days,in case of maize flour, while was(26.60 gm/10 days) in case of wheat flour. The consumption of sugar syrup increased with soybean diet (711.50 cm3)of sealed broad than the others. Also, The newly emergence workers fed on soybean cake showed the longest mean of age at (16 – 18 days)comparing with the other treatments.

ORGANIC ACIDS IN DIFFERENT TYPES OF EGYPTIAN HONEY

Organic acids in 4 types of Egyptian honey were analyzed and compared using high performance liquid chromatography (HPLC). The main types of Egyptian honeys used in this study were:Citrus, Clover, Cotton and artificial honey (or adulteration honey) which collected from colonies feeding on sugar syrup. Organic acids which present in some samples of Egyptian honey were eight types in Citrus honey, seven types in Clover honey, five types in Cotton honey and four types in artificial honey. There were only three organic acids (formic, malonic and maleic acids) common in the four experimental types of Egyptian honey. Citrus and Clover honey contains the same seven organic acids (formic, malonic, tartaric, shikimic, maleic, succinic and proponic acids), the 8th organic acid was citric acid present only in Citrus honey. The organic acids present in Cotton honey were formic, malonic, tartaric, shikimic andmaleic acids, while in artificial honey it contains formic, malonic, maleic and succinic acids. Statistical analysis represented that there were a significant difference in formic, malonic, tartaric, shikimic and maleic acid between the four tested honeys. Citric acid was present only in Citrus honey, so it can be used to differentiate between Citrus honey and the other three honeys. Also, succinic acid absent in Cotton honey so it could be used to distinguished Cotton honey from the other three honeys. So, organic acids can be used to distinguish between the main different types of Egyptian honey (Citrus, Clover and Cotton) and artificial honey (sugar syrup honey).

Macronutrient regulation in the Rasberry crazy ant (Nylanderia sp. nr. pubens)

Animals grow and optimize performance when they collect foods in amounts and ratios that best meet their species-specific nutritional requirements. For eusocial orga- nisms like ants, where only a small fraction of the colony members collect food, increasing evidence demonstrates that strong macronutrient regulation occurs at the colony level. Here, we explored regulation of protein and carbohydrate (p:c) intake in the Rasberry crazy ant, Nylanderia sp. nr. puben. We did this using dry artificial foods (14-42% total macronutrient content) having a range of fixed p:c ratios in a series of choice and no-choice laboratory experiments and used worker mortality to gauge colony-level costs associated with active nutrient regulation. Choice experiments revealed that colonies preferred carbohydrate-rich foods and self- selected a diet having a p:c ratio *1:2. No-choice experi- ments demonstrated that food p:c ratio only moderately affected worker food collection behavior, likely because colonies regulated the intake of only the non-limiting nutrients. Absolute worker mortality was generally high, but lowest in colonies feeding on the food having a p:c ratio of 1:2 (the p:c ratio ants self-selected in the choice experiment), although mortality was not significantly affected by food p:c ratio. The self-selected p:c ratio in our study is consistent with that observed in other recent ant nutrient regulation studies. Taken together, the results from these combined studies reveal emerging commonalities among ants in mac- ronutrient regulation strategies, and similarities in foraging behaviors and costs associated with macronutrient regula- tion. Finally, from a methodological perspective, the high mortality observed in our study, when compared with other recent studies, suggests that ant nutrient regulation studies should be conducted using foods having high moisture and total macronutrient content.

Colony-level macronutrient regulation in ants: mechanisms, hoarding and associated costs

Social and nonsocial organisms both require a suite of nutrients in correct amounts and ratios to promote growth and fitness, but the nutrient profiles of available foods are rarely optimal. Nutrient acquisition in insect societies is more complex compared to that of nonsocial organisms however, because foraging is restricted to only a proportion of the colony, and these members must satisfy their own nutritional requirements and those of other members having distinct nutritional needs. In this study we used laboratory colonies of the fire ant Solenopsis invicta to quantify how ants regulate their protein–carbohydrate intake when restricted to diets with different fixed protein–carbohydrate (p:c) ratios, and to quantify, at both the individual and colony level, behaviours and costs associated with nutrient regulation when feeding on these foods. We found that ants were most attracted to foods with equal or moderately protein-biased p:c ratios. However, colonies on these two treatments created large hoards, and the p:c ratios of these foods differed from that of collected food. In general, carbohydrates were extracted and protein was retained. As a result, carbohydrate intake on all diets except the extremely protein-biased diet was similar. However, carbohydrate regulation on diets with equal and moderately protein-biased p:c ratios may be costly through elevated worker activity and mortality, and through reduction of worker lipid reserves. For colonies feeding on heavily protein-biased food, energy production may have been achieved via gluconeogenesis. We discuss our results in relation to how dietary p:c imbalances in naturally encountered foods may be driving ant foraging behaviour in the field. 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Local Adaptation and Vector-Mediated Population Structure in Plasmodium vivax Malaria

Plasmodium vivax in southern Mexico exhibits different infectivities to 2 local mosquito vectors, Anopheles pseudopunctipennis and Anopheles albimanus. Previous work has tied these differences in mosquito infectivity to variation in the central repeat motif of the malaria parasite's circumsporozoite (csp) gene, but subsequent studies have questioned this view. Here we present evidence that P. vivax in southern Mexico comprised 3 genetic populations whose distributions largely mirror those of the 2 mosquito vectors. Additionally, laboratory colony feeding experiments indicate that parasite populations are most compatible with sympatric mosquito species. Our results suggest that reciprocal selection between malaria parasites and mosquito vectors has led to local adaptation of the parasite. Adaptation to local vectors may play an important role in generating population structure in Plasmodium. A better understanding of coevolutionary dynamics between sympatric mosquitoes and parasites will facilitate the identification of molecular mechanisms relevant to disease transmission in nature and provide crucial information for malaria control.

Landscape Mulches and Termite Nutritional Ecology: Growth and Survival of Incipient Colonies of <I>Coptotermes formosanus</I> (Isoptera: Rhinotermitidae)

Alate swarms are one of the major visible signs of the expansion of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in an area. Successful establishment of an incipient colony is thought to mainly rely on available food resources and moisture. The large-scale use of tree-based mulches in landscapes may inadvertently contribute to local establishment and growth of C. formosanus colonies. This research investigated the nutritional ecology of incipient colonies of C. formosanus feeding on seven tree-based, weathered, and nonweathered landscape mulches: pine straw, pine bark, cedar wood, water oak, eucalyptus, cypress, and melaleuca. Incipient colonies of C. formosanus feeding on pine straw, either weathered or nonweathered, produced significantly more progeny over the course of 1-yr feeding than colonies feeding on the other mulches tested. Regardless of weathered or not, the incipient colonies feeding on pine straw, eucalyptus, bald cypress, and water oak mulches had significantly greater survival rates after 360 d (53-77%) than colonies feeding on the other mulches tested (0-13%), but colonies feeding on nonweathered water oak had significantly lower survival (8%) than those kept on weathered water oak (58%). Colony fitness values were significantly different between the weathering treatment groups and among the different types of mulches. With regard to colony growth characteristics, three distinct growth patterns were identified: a high number of progeny (>100) with high colony survival rate (>50%), a medium number of progeny (12-50) with high colony survival rate (>50%), and a small number of progeny (0-10) with low colony survival rate (<5%). These findings suggest that different types of mulch substrates could significantly impact the nutritional ecology of the founding pairs and the successful establishment of incipient colonies during the swarming season.

Supplement Diets in Relation to Comb Building of Cross Breed Honeybee

The response of supplement diets was evaluated on comb building of cross-breed honeybee, Apis mellifera Lin. in Chitwan, Nepal during August 2000 to February 2001. The experiment was laid out in a RCB design with five replications, comprising of four feeding treatments: low dose sugar (syrup of 166 g sugar), high dose sugar (syrup of 333 g sugar), modified diet (syrup of 166 g sugar + 30 g pollen substitute) per day, and control. Each hive consisted of five farmed mellifera honeybees and each colony feeding six days with four days interval thus eleven times feedings in total were provided except for the control. Results showed that the colonies fed with modified diet (syrup of 166 g sugar combined with 30 g pollen substitute) was capable to nearly double number of combs/colony (96% increase; 9.8 combs/colony), low dose sugar feeding also increased combs by one-third (36% increase; 6.8 combs/colony) while high dose sugar syrup feeding resulted the lowest number of combs (4% increase; 5.2 combs/colony) mainly due to syrup honey collection rather than comb building. Comb building decreased in control colonies by 4% (4.8 combs/colony) perhaps due to insufficient nutrition during the dearth period. This study provided information that feeding honeybees during off-season is necessary under Chitwan conditions, while modified diet is more suitable for higher comb building of A. mellifera that could facilitate brood production, strengthen colonies, and thus contribute to honey production in flow season.J. Inst. Agric. Anim. Sci. 25:71-74 2004

About the Cover.

Next article FreeAbout the CoverPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreCoverMany invertebrates form colonies of genetically identical individuals in which some individuals become specialized for different functions. One such animal is Membranipora membranacea, a sheet-like bryozoan commonly found encrusting kelp blades in Puget Sound and many other temperate coastal areas.The main cover image shows two colonies of M. membranacea, the larger of which is 2 cm in diameter. Each of the rectangular, skeletal boxes in the colony houses an individual zooid that bears a crown of ciliated tentacles. The tentacles generate water currents that bring suspended food particles to the colony. Groups of zooids form openings (chimneys) that allow water to flow out of the colony after it has been filtered through the colony's feeding tentacles to capture food. Zooids in the center of chimneys lack feeding tentacles, but the tentacles of individuals surrounding chimneys are raised above those of their neighbors. Chimneys enhance feeding by preventing fluid pressure build-up within the colony. In the cover picture, chimneys appear as dark patches within the canopy formed by the tentacles.Because of its simple geometry and rapid growth, M. membranacea provides an excellent opportunity to investigate how fluid flow affects the development of fluid transport systems. Previous authors suggested that phenotypic plasticity in chimney spacing could be explained if water flow through the colony controls where chimneys form. To test whether water currents affect chimney formation, Michelangelo von Dassow, in a study described on pages 76-82 in this issue, injected water under the canopy of tentacles to enhance flow out the edge of the colony. In the colony shown in the upper portion of the cover image, a sheet of red light was positioned so that only the raised tentacles around chimneys were lit. As the colony grew outward, a new chimney-like opening formed distal to the polyethylene tube through which water was injected (toward the top of the image). The new opening distal to the site of water injection (right-hand tube) formed sooner than the new opening distal to the control site without water injection (left-hand tube). The ends of the tubes in the upper image were 0.8 cm apart. The observation that enhancing excurrent flow at the colony edge induced the formation of new chimneys supports the hypothesis that fluid flow controls the development of this fluid transport system. These results provide insight into the role of fluid flow in patterning animal colonies and in the development of fluid transport systems.Credits: Photos, Michelangelo von Dassow; Cover layout, Beth Liles (Marine Biological Laboratory). Next article DetailsFiguresReferencesCited by The Biological Bulletin Volume 211, Number 1August 2008 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv211n1cover Views: 39 © 2006 by Marine Biological Laboratory. All rights reserved.PDF download Crossref reports no articles citing this article.

Vitamin E supplement in honey bee colonies to increase cell acceptance rate and royal jelly production

SUMMARYThis study was carried out to determine the effects of different colony feeding methods on queen cell acceptance rates and royal jelly (RJ) production: (1) pollen substitute (PS), (2) PS + vitamin E (PS+VE), (3) sugar syrup (SS), (4) sugar syrup + vitamin E (SS+VE), and (5) no supplementary feed (control, C). Royal jelly production (g per cell) was 0.25, 0.26 0.23, 0.25 and 0.21; average colony yield (g) per harvest 32.1, 33.2, 31.0, 34.6, and 25.0; and total colony production (g) 96.2, 99.6, 93.0, 103.9, and 75.0 in groups PS, PS+VE, SS, SS+VE, and C, respectively. Any form of supplementary feeding improved RJ production relative to controls. Total colony production and average colony yield per harvest were highest in those colonies fed SS+VE or PS+VE. A benefit of supplementary VE was more apparent for sugar syrup than for pollen substitute; total colony production and average colony yield per harvest were significantly higher for SS+VE colonies than for SS, whereas no such benefit was shown between the pollen substitute groups.

Nutritional ecology of the Formosan subterranean termite (Isoptera: Rhinotermitidae): growth and survival of incipient colonies feeding on preferred wood species.

The wood of 11 plant species was evaluated as a food source significantly impacting the growth and survival of incipient colonies of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Colonies of C. formosanus feeding on pecan, Carya illinoensis (Wangenh.), and red gum, Liquidambar styraciflua L., produced significantly more progeny than colonies feeding on other wood species tested. Progeny of colonies feeding on pecan and American ash, Fraxinus americana L., had significantly greater survival than progeny of colonies feeding on other wood species. Colonies feeding on a nutritionally supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. These results indicate that differences observed in colony fitness can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species have different nutritional values to the Formosan subterranean termites. Colonies feeding on loblolly pine, Pinus taeda L., and ponderosa pine, Pinus ponderosa Laws., had significantly lower survival and produced significantly fewer workers and soldiers than colonies feeding on other wood species. Colony survival from 90 to 180 d of age and from 90 to 360 d of age was significantly correlated with the number of workers present at 90 d of colony age, indicating that colony survival depends on the presence of workers. Wood consumption in a multiple-choice study was significantly correlated with colony fitness value. This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source.

A Mixed Diet Improves Performance and Herbivore Resistance of a Parasitic Plant

I examined how the performance of Castilleja wightii (Scrophulariaceae), a generalist root parasite, is affected by the availability of different combinations of host species. In this greenhouse study, I focused on pairs of hosts consisting of either two leguminous host individuals (Lupinus arboreus; Fabaceae), two non-nitrogen-fixing hosts (Eriophyllum stachaedifolium; Asteraceae), or one individual of each of these species. Castilleja growth and reproductive performance were greatly improved by the simultaneous attack of two distinct host species, even though Castilleja grown with two Lupinus hosts had significantly higher nitrogen content. Different combinations of host species also strongly affected the growth of aphid colonies feeding on the Castilleja used in this experiment. Across all treatments, the growth of aphid colonies was positively correlated with the nitrogen content of the parasitic plants, which, in turn depended on the combination of hosts attacked. Aphid colonies feeding on parasites attacking a mixture of host species grew more slowly than those on parasites attacking two Lupinus individuals. Therefore, simultaneous attack of a mixture of host species may lead to improved parasite performance in two ways—via a direct benefit on parasite growth and flowering as well as a possible indirect benefit because of the relatively poor performance of herbivores feeding on these parasites.

A MIXED DIET IMPROVES PERFORMANCE AND HERBIVORE RESISTANCE OF A PARASITIC PLANT

I examined how the performance of Castilleja wightii (Scrophulariaceae), a generalist root parasite, is affected by the availability of different combinations of host species. In this greenhouse study, I focused on pairs of hosts consisting of either two leguminous host individuals (Lupinus arboreus; Fabaceae), two non-nitrogen-fixing hosts (Eriophyllum stachaedifolium; Asteraceae), or one individual of each of these species. Castilleja growth and reproductive performance were greatly improved by the simultaneous attack of two distinct host species, even though Castilleja grown with two Lupinus hosts had significantly higher nitrogen content. Different combinations of host species also strongly affected the growth of aphid colonies feeding on the Castilleja used in this experiment. Across all treatments, the growth of aphid colonies was positively correlated with the nitrogen content of the parasitic plants, which, in turn depended on the combination of hosts attacked. Aphid colonies feeding on parasites attacking a mixture of host species grew more slowly than those on parasites attacking two Lupinus individuals. Therefore, simultaneous attack of a mixture of host species may lead to improved parasite performance in two ways—via a direct benefit on parasite growth and flowering as well as a possible indirect benefit because of the relatively poor performance of herbivores feeding on these parasites.

Effects of selected insecticide formulations, phased application and colony management strategies on honey bee mortality in processing sweetcorn

SUMMARYThese studies were undertaken to evaluate different strategies for reducing losses of honey bees (Apis mellifera) due to the use of insecticides in commercial sweetcorn (Zea mays) production fields. The strategies were: (1), insecticide application timed to avoid peak flowering periods in sweetcorn; (2), insecticide formulation, including carbofuran, encapsulated methyl parathion, permethrin and a tank mix of car- baryl plus parathion; (3), the use of pollen traps to prevent contaminated pollen coming into the hive; and (4), feeding (engorgement) of colonies with sugar syrup immediately following insecticide application to reduce honey bee foraging. Timing of insecticide applications was ineffective and a practical impossibility. Bee mortality was less with permethrin than with the other materials tested. Pollen traps and colony feeding may reduce bee mortality under some circumstances; however, these strategies proved unreliable and further study is needed. The data show that bees foraging on ragweed (Ambrosio spp.) adjacent to sweetcorn fields, rather than on sweetcorn, may be responsible for generating the excessive bee losses associated with sweetcorn. The results further indicate that circumstances in each field are unique due to prevailing conditions at each site, e.g. clean cultivation, competing resources, insecticide tank mixes, and other nearby applications. Finally, we find it highly significant that we were unable to induce high levels of bee mortality by applying our test compounds at the rate given by the manufacturers.

Comparative fertilization biology of gymnolaemate bryozoans

Locations and oogenic stages of eggs at the time of sperm-egg fusion were determined for nine gymnolaemate species exhibiting different reproductive strategies with respect to site of embryonic development (e.g., water column, introvert, embryo sac, or ovicell) larval type, and zooid sexuality. Ovarian, coelomic, and recently spawned oocytes obtained from freshly collected colonies between 1988 and 1995 were stained with aceto-orcein and examined for the presence of a sperm nucleus. All nine species are shown to have a similar fertilization biology in which sperm fuse with eggs in or near ovaries and egg activation is delayed until eggs are spawned. In species such as the etenostomeAlcyonidium sp. and the cheilostomeElectra pilosa (Linnaeus, 1767), which produce marierons oocytes that are spawned into the water column and have cyphonautes larvae, sperm fuse with late growth stage ovarian oocytes after germinal vesicle breakdown (GVBD) at or near ovulation. In species that produce few oocytes, brood embryos, and release coronate larvae, sperm fuse with late growth stage ovarian primary oocytes before GVBD, as in the ctenostomeBowerbankia gracilis Leidy, 1855, or with very early growth stage ovarian primary oocytes, as in the cheilostomesCribrilina corbicula (O'Donoghue, 1923),Dendrobeania lichenoides (Robertson, 1900),Hippodiplosia insculpta (Hincks, 1882),Schizoporella serialis (Heller, 1867),T ricellaria gracilis (Smitt, 1867), andWatersipora arcuata Banta, 1969. Fertilization success was high in all nine species, with 83 to 100% of oocytes at an appropriate oogenic stage containing a sperm nucleus or early male pronucleus. Gymnolaemate bryozoans may maintain high levels of fertilization success by: (1) concentrating spawned sperm from the water column using colony feeding currents; (2) localizing sperm-egg encounters in or near the ovary, (3) using sperm when available by permitting sperm to fuse with early growth stage oocytes; and (4) selfing.

The effects of flow on feeding of three gorgonians from southern Taiwan

The feeding performances of three gorgonians, Subergorgia suberosa, Melithaea ochracea, Acanthogorgia vegae, in different flow regimes were studied. The three gorgonians expanded their polyps and fed in varying ranges of flow velocities. Differences in the feeding range are possibly related to polyp morphologies. S. suberosa, which has tall polyps and encounters higher drag, is more easily deformed in currents; it feeds in a narrow range of flow velocities (7–9 cm·s −1). M. ochracea, which has short polyps and encounters lower drag, is less readily deformed in currents; it feeds in a wider range of flow velocities (4–40 cm·s −1). Polyp heights of A. vegae are intermediate and this coral feeds in currents of 2–22 cm·s −1. The upper limits on the flow ranges are considered to be determined by the balance between the energy gained from feeding and the cost of keeping the polyps expanded. Optimal feeding rates of the three gorgonians were found at moderate flow velocities. Feeding rates increased initially with flow velocity, reached a peak value at 8 cm·s −1, then decreased with increasing flow velocities. Both the colony feeding effectiveness and the polyp feeding effectiveness at 8 cm·s −1 are ranked: S. suberosa >A. vegae>M. ochracea.