Austrosimulium (Austrosimulium) dumbletoni n.sp. from New Zealand (Diptera: Simuliidae)

The female of Austrosimulium (Austrosimulium) dumbletoni n.sp. is described and compared with other New Zealand species in the subgenus. Females were captured while they were biting caged Fiordland crested penguins, Eudyptes p. pachyrhynchus. They are vectors of the blood parasite Leucocytozoori tawaki.     

Direct and indirect effects of dragonfly (<Emphasis Type="Italic">Anax imperator</Emphasis>) nymphs on green toad (<Emphasis Type="Italic">Bufo viridis</Emphasis>) tadpoles

We conducted an artificial pond experiment to assess the direct and indirect effects of predation on Bufo viridis tadpoles. We ran three treatments: free Anax (unrestrained predatory dragonfly nymph Anax imperator), caged Anax (non-consumptive effects), and control (no Anax). Anax showed both strong consumptive and non-consumptive effects on Bufo tadpoles. Free Anax eliminated all of the tadpoles within six days. Tadpoles preferred the shady side of the ponds. Caged Anax caused tadpoles to increase their spatial preferences. Tadpoles avoided the center of the pond, and in the presence of the caged predator, they were found in the center even less. Tadpoles also showed a strong preference for crowding together, and in the presence of a caged Anax, they tended to crowd more. Moreover, Bufo metamorphosed earlier and at a larger size in the caged Anax ponds, possibly by providing extra food resources due to the extra organic matter excreted by the predators. Handling editor: K. Martens     

Serological Evidence of <Emphasis Type="Italic">Paracoccidioides brasiliensis</Emphasis> Infection in Chickens from Paraná and Mato Grosso do Sul States,Brazil

The objective of this study was to detect antibodies against Paracoccidioides brasiliensis in free-range and caged chickens Gallus domesticus. Initially, the humoral immune response of two chickens immunized with P. brasiliensis was evaluated. Both animals showed the production of antibodies to gp43, the major P. brasiliensis antigen. The seroepidemiological survey was conducted in chickens from the Pantanal region in Mato Grosso do Sul State (free-range n = 40) and from northern region of Paraná State (free-range n = 100, caged n = 43). The serum samples were analyzed by indirect ELISA using gp43 as antigen. The positivity observed in free-range chickens from Mato Grosso do Sul (55%) was significantly higher (P = 0.0001) than in free-range chickens from Paraná State (16%). In contrast to the free-range chickens, no positivity was observed in the caged chickens (P = 0.003). This is the first report showing serological evidence of P. brasiliensis infection in chickens. The results suggest that free-range chickens are more frequently infected by P. brasiliensis, probably due to the constant contact with soil than caged chickens and could be useful as epidemiological markers of paracoccidioidomycosis.     

Evidence for sexual attraction pheromones released by male tropical donkey's ear abalone (Haliotis asinina), (L.)

Abstract

The tropical donkey's ear abalone (Haliotis asinina) is routinely collected in many parts of the Indo-Pacific and has significant potential for commercial aquaculture. Although its reproductive cycle has been investigated, no studies have reported the use of chemical signals to coordinate reproduction and spawning. Using a bioassay designed with one caged individual, whilst the other is free to roam, we investigated the presence of attraction pheromones released from mature individuals. Only mature females were attracted to caged mature males with all other treatments showing no significant attraction. Those mature females also took significantly less time to reach the mature males than other pairings. Temperature influenced the response with the maximum number of positives occurring between 25 and 31°C, which coincides with the optimum physiological temperatures and the spawning times for this species. We have also shown that the attraction pheromone is present in mature male testes and induces stereotypical pre-spawning behaviours (sweeping epipodial and cephalic tentacles) as well as attracting females. Some individuals also moved towards the surface of the water, this may also be a pre-spawning behaviour. This is the first time that a sexual attraction pheromone has been reported for any haliotid species and is likely to have a critical function in the synchronization of spawning in the wild between sexes.     

Second-messenger-induced signalling events in pollen tubes of Papaver rhoeas

A role for cytosolic free Ca²⁺ (Ca²⁺_i) in the regulation of growth of Papaver rhoeas pollen tubes during the self-incompatibility response has recently been demonstrated [Franklin-Tong et al. Plant J. 4:163–177 (1993); Franklin-Tong et al. Plant J. 8:299–307 (1995); Franklin-Tong et al. submitted to Plant J.]. We have investigated the possibility that Ca²⁺_i is more generally involved in the regulation of pollen tube growth using confocal laser scanning microscopy (CLSM). Data obtained using Ca²⁺ imaging, in conjunction with photolytic release of caged inositol 1,4,5-trisphosphate [Ins(1,4,5)P₃], point to a central role of the phosphoinositide signal transduction pathway in the control of Ca²⁺ fluxes and control of pollen tube growth. These experiments further revealed that increases in cytosolic levels of Ins(1,4,5)P₃ resulted in the formation of distinct Ca²⁺ waves. Experiments using the pharmacological agents heparin, neomycin and mastoparan further indicated that Ca²⁺ waves are propagated, at least in part, by Ins(1,4,5)P₃-induced Ca²⁺ release rather than by simple diffusion or by “classic” Ca²⁺-induced Ca²⁺ release mechanisms. We also have data which suggest that Ca²⁺ waves and oscillations may be induced by photolytic release of caged Ca²⁺. Ratio-imaging has enabled us to identify an apical oscillating Ca²⁺ gradient in growing pollen tubes, which may regulate normal pollen tube growth. We also present evidence for the involvement of Ca²⁺ waves in mediating the self-incompatibility response. Our data suggest that changes in Ca²⁺_i and alterations in growth rate/patterns are likely to be closely correlated and may be causally linked to events such as Ca²⁺-induced, or Ins(1,4,5)P₃-induced wave formation and apical Ca²⁺ oscillations.Presented at the 1997 SEB Annual Meeting: Interactive MultiMedia Biology - Experimental Biology Online Symposium, Canterbury, 7-11 April     

Performance of Symydobius americanus (Homoptera: Aphididae) on paper birch grazed by caterpillars

Abstract.

• 1 The potential for host plant-mediated interactions between leaf-chewers and the aphid Symydobius americanus on paper birch (Betula papyrifera) was investigated experimentally.
• 2 Datana ministra and Malacosoma disstria caterpillars were caged on randomly chosen, undamaged branches until they had eaten 30–50% of the leaf area. Control branches received cages but no larvae.
• 3 Alates of S.americanus were than caged on the experimental and control branches to assess the effect of chewing damage on colony performance.
• 4 Chewing damage had no detectable effect on initiation of alate reproduction, development time, mortality of nymphs or colony growth rate.

     

Marine reserves demonstrate trophic interactions across habitats

Several infaunal bivalve taxa show patterns of decreased biomass in areas with higher densities of adjacent reef-associated predators (the snapper, Pagrus auratus and rock lobster, Jasus edwardsii). A caging experiment was used to test the hypothesis that patterns observed were caused by predation, using plots seeded with a known initial density of the bivalve Dosinia subrosea to estimate survivorship. The caging experiment was replicated at several sites inside and outside two highly protected marine reserves: predators are significantly more abundant inside these reserves. Survivorship in fully caged, partially caged and open plots were then compared at sites having either low (non reserve) or high (reserve) predator density. The highest rates of survivorship of the bivalve were found in caged plots inside reserves and in all treatments outside reserves. However, inside reserves, open and partially caged treatments exhibited low survivorship. It was possible to specifically attribute much of this mortality to predation by large rock lobsters, due to distinctive marks on the valves of dead D. subrosea. This suggests that predation by large rock lobster could indeed account for the distributional patterns previously documented for certain bivalve populations. Our results illustrate that protection afforded by marine reserves is necessary to investigate how depletion through fishing pressure can change the role of upper-level predators and trophic processes between habitats. Electronic Supplementary Material Supplementary material is available for this article at An erratum to this article can be found at     

Importance of early arrival of adult <Emphasis Type="Italic">Harmonia axyridis</Emphasis> for control of <Emphasis Type="Italic">Aphis spiraecola</Emphasis> on apple

The biological control of aphid populations may only be possible when natural enemies arrive soon after aphid colonization. This study was done to identify how quickly adult Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) need to arrive at newly established spirea aphid [Aphis spiraecola Patch (Homoptera: Aphididae)] colonies on apple (Malus domestica Borkh.) to provide population control. A total of 100 newly established spirea aphid colonies were caged in an experimental apple orchard in West Virginia, USA. A single adult H. axyridis was added to each of ten caged colonies at day 0, 5, 10, 15 and 20 days after caging. An additional ten caged colonies were opened for exposure to natural levels of predation at each of the treatment intervals as a control. The single H. axyridis eliminated the aphid colonies significantly more quickly than natural predation for up to ten days after colony establishment. The probability of an aphid colony producing alates was significantly lower in the presence of a single H. axyridis adult than when exposed to natural predation for the first ten days. Adult H. axyridis beetles are capable of completely controlling individual spirea aphid colonies on apple only if they are abundant enough to find colonies within one week of colony establishment.     

THRIPS-MEDIATED SELF-POLLINATION OF TWO FACULTATIVELY XENOGAMOUS WETLAND SPECIES

Thrips and/or aphids played an important role in the self-pollination of two facultatively xenogamous herbs that inhabit wetlands in northwestern Iowa. In both Ranunculus sceleratus and Potentilla rivalis the fruit set and/or successful pollination of plants that were sprayed with malathion to kill thrips and aphids and caged to exclude typical flower visitors was substantially and significantly lower than that of open-pollinated and caged plants. We observed pollenbearing thrips and aphids on the flowers. The high fruit sets of emasculated flowers of R. sceleratus showed that insects moved pollen between flowers, and our observations of bees collecting pollen and moving between plants suggest that cross-pollination can occur in both species.     

Mosquito female response to the presence of larvivorous fish does not match threat to larvae

1. Several species with complex life‐history traits such as amphibians and insects with aquatic immature stages and terrestrial adults avoid ovipositing in pools containing larvivorous fish. This avoidance response was assumed to be a general one for most fish species. 2. The generality of ovipositing Culex to the presence of three, widespread larvivorous fish species was tested in a set of field experiments with artificial oviposition pools using caged fish. 3. Larval performance was further examined under actual predation by these three fish species. 4. Results show that ovipositing females responded strongly to the presence of caged mosquitofish, Gambusia affinis, while showing no significant response to the presence of caged green sunfish, Lepomis cyanellus, or the pirate perch, Aphredoderus sayanus. All three fish species consumed similar amounts of larvae. 5. This is the first example of species‐specific response differences to predators during mosquito oviposition habitat selection. These results point to the existence of predator‐released kairomones affecting mosquito behaviour. These kairomones may either be species‐specific or vary in concentration among fish, and probably have an important role in the understanding of mosquito spatial distribution.     

Photoperiodic and ambient temperature control of the annual body mass cycle in Svalbard ptarmigan

The present study describes the photoperiodic control of annual body mass changes in captive. Svalbard ptarmigan, in particular the onset of autumnal increase and midwinter decrease in fat content under natural and simulated daylight-conditions in Tromsø (69° 46 N). Autumnal fattening commences when the birds become photorefractory and presumably depends on this condition. At present it is not known if any causal relationship is involved. Under outdoor ambient temperature, body mass begins to decline in November. However, when Svalbard ptarmigan are caged indoors at higher ambient temperatures and exposed to natural or simulated annual changes in daylength, body mass remains high until February. In these birds the depletion of fat stores appears to be triggered by the increasing daylength, since body mass remained high under permanent exposure to short days throughout spring but decreased promptly following photostimulation in May. When ptarmigan caged indoors were starved in midwinter body mass fell but increased briefly upon refeeding and thereafter declined as in the control birds throughout spring. This indicates that the winter body mass profile in Svalbard ptarmigan is not merely the passive outcome of shifts in the energy expenditure associated with thermoregulation, and that a sliding set point for body mass exists and is temporally fixed at the seasonal maximum in mid winter in birds caged under indoor ambient temperatures. The possibility is discussed that the decline in body mass seen outdoors may be associated with the increased hypothalamus-pituitary-gonadal activity which follows the breaking of photorefractoriness, and that this activity is sufficiently suppressed in Svalbard ptarmigan caged indoors under exposure to short days, to delay the reduction until they are photostimulated.Abbreviations BM body mass - GH growth hormone - HPG hypothalamic-pituitary-gonadal system - LL continous light - NL natural light - SD short day (4 hours light per day) - SL simulated annual changes in daylength - T _a ambient temperature     

Effectiveness of nectarivorous birds and honeybees as pollinators of Banksia spinulosa (Proteaceae)

Abstract The effectiveness of nectarivorous birds and honeybees (Apis mellifera) as pollinators of Banksia spinulosa (Proteaceae) was investigated. Birds visited inflorescences in the early, mid and late flowering seasons. In contrast, honeybees visited only on days in the late flowering period when maximum temperatures exceeded 15°C. Self pollen remained on pollen presenters of flowers for up to 5 days in the early and mid periods. In the late period, when honeybees visited inflorescences, self pollen was removed within 2 days. Pollen removal was similar for caged (birds excluded) and open inflorescences in the late period, indicating that most pollen was removed by honeybees. In the early and mid periods, honeyeaters pollinated 22% and 27% of flowers on open inflorescences, respectively. In the late period, when both birds and bees visited inflorescences, 64–73% of flowers on open inflorescences were pollinated. Foraging by honeybees resulted in pollen deposition as 38% of flowers on caged inflorescences were pollinated. Throughout the flowering season a similar number of pollen grains was deposited per stigma. There were 3.0–3.7 pollen grains per stigma on open inflorescences in the late period, although only 2.0 grains per stigma on caged inflorescences. In the early and mid periods, fewer caged than open inflorescences produced fruits, indicating the importance of honeyeaters to reproductive success at these times. In contrast, in the late period when honeybees visited inflorescences, fruit-set was similar on caged and open inflorescences. Overall, these results indicate that honeybees were effective pollinators of B. spinulosa.     

Synthesis of Photolabile Caged Amino Acids for Measuring Amino Acid Transporters

Photolabile precursors (caged compounds) of amino acids such as Ala, Leu, Lys, and Ser were prepared by some simple reactions. These compounds were designed for the rapid, photochemically initiated release of amino acids. These amino acid transporters were expressed in Xenopus oocyte by injecting mRNA prepared from rat kidney. The electrical response of each transporter was examined by applying the amino acids and caged compounds before and after photolysis. Photolysis of the caged amino acids increased the electrical response of the facilitated amino acid transporters expressed in the oocyte. Consequently, these synthesized caged amino acids would be applicable to kinetic investigations on the transporters when combined with a pulsed laser or xenon arc flash lamp.     

The influence of natural enemies on brood production inIps typographus (Col. scolytidae) with special reference to egg-laying and predation byThanasimus formicarius (Col.: Cleridae)

The predatorThanasimus formicarius (L.) (Coleoptera, Cleridae) and its preyIps typographus (L.) (Coleoptera, Scolytidae) were studied in the laboratory and the field. In the laboratory, 11T. formicarius laid 71–132 eggs (mean=162) during 66–123 days. During this time they ate 66–132I. typographus adults per pair (male +female). The number of eggs laid per female was not correlated with life span or the number ofIps eaten. In the field, predation byT. formicarius larvae and other natural enemies onI. typographus brood was studied in the last year of an outbreak. Caged and uncaged spruce bolts attacked byI. typographus were used, and pairs ofT. formicarius were released in the cages. The treatments were: uncaged bolts, caged bolts withoutT. formicarius, caged bolts with 4T. formicarius pairs, and caged bolts with 8T. formicarius pairs. The productivity ofI. typographus was highest in the caged bolts withoutT. formicarius (mean=4.5 offspring/female) and lowest in the uncaged bolts (mean=0.9 offspring/female). The density ofI. typographus galleries was similar in the different treatments. Hence, the variation in productivity between treatments could not have been due to differences in the levels of intraspecific competition. There was no difference in bark beetle productivity or density ofT. formicarius larvae between bolts with 4 pairs ofT. formicarius and bolts with 8 pairs (mean=2.5 offspring/female). This indicates that some kind of interference occurred betweenT. formicarius individuals (e.g. cannibalism) and that a maximum level of predation was reached. Predation by larvae ofMedetera spp. (Diptera, Dolichopodidae),Thanasimus spp. and other beetles, and parasitism by wasps (Hymenoptera, Pteromalidae) probably caused the low productivity in the uncaged bolts.      

Behavioural responses of female Queensland fruit fly, Bactrocera tryoni, to mineral oil deposits

Behavioural responses of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), females to fruit dipped in water and fruit dipped in 0.5% (vol/vol) aqueous emulsions of a mineral oil were determined and analysed. The mineral oil was an nC20–22 distillation fraction of the base oil used to produce an nC23 horticultural mineral oil. Females caged with oil‐treated fruit had significantly longer prelanding intervals than females caged with water‐dipped fruit. The latter was attacked immediately or shortly after being caged with flies whereas some oil‐dipped fruit was not attacked within 180 min. The percentage of landings that led to oviposition on water‐ and oil‐treated fruit were 58 and 13%, respectively, and the percentages ovipositing after probing were 74 and 25%, respectively. Likewise, average times spent probing were 7 vs. 31 s whereas average times spent ovipositing were 321 vs. 223 s. Females spent less than half as much time on oil‐treated fruit than on water‐treated fruit. Transition probabilities of rejection, when applied to the behaviour sequence indicated that oil‐treated fruits are about nine times less likely to be infested with B. tryoni.     

Hybrid carrot seed crop pollination by the fly Calliphora vicina (Diptera: Calliphoridae)

Many insect species can contribute to crop pollination; however, most growers remain highly dependent on the managed honey bee (Apis mellifera L.) for this service. The European Blue Blow Fly Calliphora vicina Robineau‐Desvoidy, 1830 is one species with potential use as a pollinator. It occurs worldwide and is easy to rear. Caged trials conducted within a hybrid carrot (Daucus carota L.) seed crop found C. vicina to be an effective pollinator. Seed yield (number and weight) from field‐grown carrot plants caged with C. vicina, but excluding all other large flower visitors (body width > 3 mm), was similar to seed yield from uncaged plants in the presence of honey bees (Apis mellifera L.) and other insects. In contrast, caged plants without C. vicina produced 10‐fold less seed. Under open field conditions, C. vicina spent an average of 71.0 s per umbel compared to 54.4 s for honey bees; however, under caged conditions, C. vicina spent more time on average per umbel (128.9 s). Counts of C. vicina and honey bees on umbels outside of cages and C. vicina inside cages found that honey bees were most abundant on days with maximum temperature > 25°C, while C. vicina was more abundant on cooler days around 20°C. C. vicina may therefore be a useful pollinator of crops grown in isolation cages for plant breeding purposes as well as in open fields when climatic conditions are less favourable for optimal honey bee activity.     

Functional response ofChrysopa carnea [Neur: Chrysopidae] larvae feeding onHeliothis virescens [Lep.: Noctuidae] eggs on cotton in field cages

The functional response of 3rd instarChrysopa carnea (Stephens) larvae feeding on 4 densities ofHeliothis virescens (F.) eggs was determined on caged cotton (Gossypium hirsutum L.).C. carnea larvae had a mean search rate of 1.08×10⁻⁵ ha/predator-day or 0.11 row-m/predator-day.      

Location of Biomphalaria pfeifferi by Schistosoma mansoni miracidia in stagnant and running water under field conditions

The efficiency of S. mansoni miracidia in locating and infecting Biomphalaria pfeifferi in Gezira canals has been studied under field conditions. When S. mansoni eggs were introduced into clean stagnant water in small field channels, the miracidia hatched to infect 100% of 30 snails in cages at the release point. Fifteen metres upstream and downstream 13% of caged snails were infected but no infections were found in snails 20 m away.When eggs were released into the same canal in flowing water (8.3 cm · s^–1), no infections were detected in any of the caged snails placed 0–100 m downstream. Releasing hatched miracidia instead of eggs resulted in infections in all cages at 5 m intervals from 0-100 m. The release of eggs into flowing water was likened to the method by which S. haematobium eggs are deposited during urination. The 0% infection suggests that eggs will be swept away from the point of contamination by the flow. Thus only urination into stagnant water will lead to heavy snail infection rates.When eggs were released into a small pond-like minor canal tail end snail infection rates were only 3%. This was probably due to the larger water volume, smaller number of caged snails, and the presence of vegetation and other fauna which may be decoys or predators.The results highlight how very high snail infection rates can be produced under ideal conditions but also show how large snail and miracidia numbers are required in natural situations.     

Synchrony of estrous swelling in captive group-living chimpanzees (Pan troglodytes)

Recent findings suggest that menstrual synchrony may occur in humans and is more dependent on factors of close personal association than simple prox imity. Part I of this study analyzed the estrous cycles of 10 captive group living chimpanzees (Pan troglodytes) housed in two separate groups in the same building. Each group contained at least one male. The mean discrepan cies for (1) the approximate day of ovulation (last day of maximum swelling) and (2) the day of onset of estrous swelling were determined for all possible pairs within groups and compared to the mean discrepancies of pairs between groups. With respect to the probable day of ovulation, the mean discrepancy of animals caged together was 8.0 days and that of animals caged separately was 10. 7 days. Comparing the onset of estrous swelling, the mean between groups was 10.4 days, whereas females caged together averaged only 5.7 days. A repeated-measures analysis of variance indicated a significant group effect in the onset of estrous swelling (F = 5.68,p < 0.05), whereas there was no significant difference between the animals caged together and those caged separately with respect to the last day of maximum swelling (F = 1.37, NS). Part II of the study compared the onset of the first postpar tum estrus (PPE) to the onset of estrus in cagemates. During a 6-year period, 13 females exhibited 33 PPEs while in social contact with cycling females. Of 86 paired comparisons, the PPE onset of 43 (50%) occurred with in 6 days of the swelling onset of a cagemate. The results suggest that, as in other species (including humans), the social contact and time spent together influence the synchrony of chimpanzee estrous cycles, especially in terms of swelling onset. The synchrony of estrous swelling and possible mediation by olfactory and/or hormonal cues are discussed as they relate to chimpanzee social structure and female reproductive strategy.     

Effects of social conditions on adult and subadult female rat-like hamsters (<Emphasis Type="Italic">Cricetulus triton</Emphasis>)

As a solitary species, rat-like hamsters (Cricetulus triton) still live in family groups before they become mature and leave their families for a solitary life. This study aimed to investigate by a laboratory experiment if housing conditions have a different effect on physiological aspects of immature and mature females. We found that paired caged adult females became significantly heavier than their original weights; whereas the singly caged did not show significant change in their body weight. Although the subadults body weights increased significantly compared to their initial weights in both paired or singly caged groups, significant changes in body weight did not occur between the two groups. Although spleen and adrenal gland sizes were not significantly different between the two adult groups, the cortisol levels were significantly elevated by paired caging. In subadults, the adrenal size of the singly caged group was larger than that in the paired caged group despite there being no significant difference in cortisol level. Flank glands became significantly larger in paired caged adults than in singly caged adults, and there were no significant differences in subadults between the two groups. Additionally, ovaries and uteri of the paired caged adult females were comparatively lighter than those of the singly caged group; in contrast, ovaries and uteri of the paired caged group were larger than those of the singly caged group in subadults, although progesterone and estradiol levels did not show significant differences between the two adult groups. These different changes in physiological traits caused by housing conditions indicated that paired caging depressed adults and facilitated subadults; isolation facilitated adults and depressed subadults.