Survival of caddis larvae in relation to their case material in a group of temporary and permanent pools

1. The occurrence of larvae of Limnephilus coenosus and L. vittatus (Trichoptera) was recorded in 103 rock pools both before and after the dry periods in spring–summer (April–May and July–early August), when a great number of the pools dried out. In early spring, 84% of the pools sampled contained larvae of at least one of the species. Limnephilus coenosus larvae were present in a higher proportion of pools that later dried out than in the permanent ones, while L. vittatus larvae were predominantly found in permanent pools. Larvae of both species were found together in 31% of the inhabited pools.
2. Laboratory experiments, designed to elucidate differential survival under drought conditions, demonstrated that the organic cases of L. coenosus larvae held water more efficiently than did the mineral L. vittatus cases. Full-grown (fifth instar) L. coenosus larvae also survived dry conditions better than did L. vittatus larvae. The higher survival of L. coenosus was due to a combination of drought-resistant case material and a higher survival ability of the larvae themselves.
3. Limnephilus vittatus larvae were restricted by their low capability to withstand desiccation, although case material and food were available for L. vittatus larvae in all pools. Absence of case material and high-quality food in many pools, however, restricted the presence of L. coenosus larvae, but this species did not suffer from heavy mortality because of desiccation and all pool populations of L. coenosus survived until pupation.
4. The differences in species composition in these temporary and permanent pools can be explained by the differential site selection by ovipositing females, as well as by larval survival. The intrinsically greater survival of L. coenosus larvae during drought, together with the water-retaining properties of the cases, allowed this species to exploit stressful and risky habitats, such as temporary pools.     

Survival of caddis larvae in relation to their case material in a group of temporary and permanent pools

1. The occurrence of larvae of Limnephilus coenosus and L. vittatus (Trichoptera) was recorded in 103 rock pools both before and after the dry periods in spring–summer (April–May and July–early August), when a great number of the pools dried out. In early spring, 84% of the pools sampled contained larvae of at least one of the species. Limnephilus coenosus larvae were present in a higher proportion of pools that later dried out than in the permanent ones, while L. vittatus larvae were predominantly found in permanent pools. Larvae of both species were found together in 31% of the inhabited pools.
2. Laboratory experiments, designed to elucidate differential survival under drought conditions, demonstrated that the organic cases of L. coenosus larvae held water more efficiently than did the mineral L. vittatus cases. Full-grown (fifth instar) L. coenosus larvae also survived dry conditions better than did L. vittatus larvae. The higher survival of L. coenosus was due to a combination of drought-resistant case material and a higher survival ability of the larvae themselves.
3. Limnephilus vittatus larvae were restricted by their low capability to withstand desiccation, although case material and food were available for L. vittatus larvae in all pools. Absence of case material and high-quality food in many pools, however, restricted the presence of L. coenosus larvae, but this species did not suffer from heavy mortality because of desiccation and all pool populations of L. coenosus survived until pupation.
4. The differences in species composition in these temporary and permanent pools can be explained by the differential site selection by ovipositing females, as well as by larval survival. The intrinsically greater survival of L. coenosus larvae during drought, together with the water-retaining properties of the cases, allowed this species to exploit stressful and risky habitats, such as temporary pools.     

Food sources and foraging tactics in tropical rain pools

Pools on exposed rocks are common over much of Africa. Based on dimensions and position, those examined are of three types. Each type is inhabited by larvae of virtually a single dipteran species at high densities (over two million larvae m^-2).
Location of the pools suggests that food might be a limiting factor. However, events, including defecation in pools by civets and genets, fruit fall and wind-borne pollen, apparently ensure that this is not the case. In this environment of superabundance animals are presumably free to choose favoured items of food.
Each animal species does, indeed, take a characteristic assemblage of food items. However, each species is shown to eat whatever it can swallow, differences in gut contents being due to differences in the characteristic food items available in each type of pool. Most algae are excluded because they are too large or inaccessible, which means that the pool food chains are based largely on allochthonous detritus. There is no reason to believe that food type, perse , has any influence in determining which of the three dipteran species is present.     

The effect of tadpoles on algal growth in temporary, rain-filled rock pools

SUMMARY.

• 1 Small, temporary, rain-filled rock pools in Malawi, Central Africa, are colonized by algae, insect larvae and tadpoles. Algal growth in these pools is largely controlled by nutrient supply, flushing rate and the presence of tadpoles.
• 2 Dissolved nitrogen and phosphorus concentrations were usually high following filling but subsequently declined. Nitrogen supply may limit algal growth at times. The flushing rate of the pools is an over-riding factor in determining the population size of floating algae.
• 3 Experiments and field observations showed that tadpoles apparently, paradoxically, promoted the growth of the epineustic and phytoplanktonic algae on which they grazed. The explanation of this paradox probably has in the transfer, by the tadpoles, of nutrients from the sediments to the overlying water. This nutrient enrichment stimulates the growth of the epineuston and phytoplankton.

     

Survival strategies in tropical rain pools

Summary Adaptations of three larval diptera in central Africa, each inhabiting rain-filled rock pools of characteristic duration, have been studied by field observation and experiment.The duration of the pool is important in determining which of the three species is present. Large pools, lasting a few weeks after each rain, favour Chironomus imicola which has a larval life span of as little as twelve days. This species relies on egg laying female flies to re-invade newly filled pools. In cases where the pool lasts for a shorter time than the minimum larval life span a mechanism is needed to survive dry periods in situ. Such pools are inhabited by larvae of Polypedilum vanderplanki and Dasyhelea thompsoni. Larvae of P. vanderplanki are poor at invading newly flooded pools and are also poor at competing with other species. However they are able to tolerate virtually a complete loss of body water and are therefore able to survive drought in the dry mud. They are consequently always the first there after refilling, a factor that provides them with sufficient advantage to eventually become established in very small pools. D. thompsoni larvae, not quite so good at surviving drought, but better at invading, occupy pools of intermediate size. They probably inhabit a larger number of pools than either of the other two species.A hazard associated with surviving dry phases in situ is vulverability to attack by terrestrial scavengers. However the activity of scavengers such as pheidolid ants, although conspicuous, is confined to periods when standing water has evaporated but the mud is still moist. Once dry, predation stops. Losses from this cause are therefore likely to be associated with periodic dry phases throughout the rainy season rather than with the dry season itself.     

Oviposition habitat selection by the mosquito, Culiseta longiareolata: effects of conspecifics, food and green toad tadpoles

Abstract. 1. Ovipositing females should choose egg-laying sites which maximize the growth and survivorship of their offspring. Accordingly, they should avoid habitats with high densities of competitors and predators and should choose sites with adequate food. We tested experimentally the oviposition response of the mosquito, Culiseta longiareolata Macquart, to extra food and two species which are both potential competitors and predators of its offspring: conspecific larvae and green toad ( Bufo viridis ) tadpoles.
2. We conducted the experiment in outdoor artificial pools where wild C. longiareolata females were presented with choices of all combinations of the presence or absence of: (1) C.longiareolata larvae, (2) B.viridis tadpoles, and (3) extra food (a mixture of ground fish food and mouse chow).
3. Oviposition rates averaged approximately 4 times greater in response to extra food.
4. The presence of the tadpoles, particularly later in the experiment when they were larger, caused a significant reduction (approximately 50%) in oviposition rate.
5. We did not detect a statistically significant effect of conspecific larvae on oviposition habitat selection.
6. Our results indicate that Culiseta females choose habitats for oviposition based on food availability. They also tend to avoid habitats containing Bufo tadpoles, presumably to avoid predation and/or competition.     

Factors influencing tadpole deposition site choice in a frog with male parental care: An experimental field study

Parents have evolved a variety of strategies to minimize risks to their offspring, including complex choices regarding suitable rearing sites, based on abiotic and biotic factors, which differentially affect offspring survival. Because availability and quality of these sites are variable, parents may have to choose between immediately available lower‐quality rearing sites or extended search time. In some frog species with larval transport, parents are known to select bodies of water that are free of predators, cannibalistic tadpoles, or intraspecific competitors for larval deposition and rearing sites. We tested whether abiotic factors and the presence of predators and conspecific tadpoles affect tadpole deposition behavior in a population of smooth guardian frog, Limnonectes palavanensis, on the island of Borneo. Females lay eggs on land and males guard them until they hatch; after hatching, tadpoles climb onto the male's back and are subsequently transported to small pools of water on the forest floor, which are scarce and patchily distributed. We estimated the abundance of natural tadpole rearing sites in our study area and conducted experiments using artificial pools to test whether abiotic characteristics of these pools affect the probability of larval deposition. We also performed choice experiments to test whether males of L. palavanensis avoid pools with conspecific tadpoles or predators. Lastly, we tested whether the tadpoles of this species exhibit cannibalism. The abundance of natural deposition sites was low, and males readily used artificial pools for tadpole deposition. Males were less likely to deposit tadpoles in artificial pools located in steep areas, and males did not avoid depositing tadpoles in pools with conspecifics or with experimentally introduced predators. Males exhibited clutch‐partitioning behavior, dividing tadpoles between adjacent artificial pools. Pool availability, rather than the presence of potential competitors or predators in a pool, affects tadpole deposition decisions in this species.     

Rain-pools on peat moorland as island habitats for midge larvae

A common aquatic habitat on peat moorland is a pool, often only a few centimetres deep. Many have a shorter average duration than that of the inhabitants but they are, nonetheless, inhabited by the larval stages of several chironomid species at moderately high densities. Because of their durational characteristics, these pools might be expected to have an endemic fauna, as is the case in similar ephemeral island habitats elsewhere. However, we find no such fauna. Indeed, we find no qualitative difference between them and permanent pools of the same substratum.We identify three reasons for the apparent absence of endemism. First, the midge fauna is able to survive dry periods in the moist mud, so that even the smallest pools are effectively permanent from the adaptive point of view. Second, although seasonal freezing eliminates the fauna of smaller pools, larvae are able to complete their development in the preceding summer. Third, nearby permanent pools which do not dry and in which the mud does not freeze, may act as refugia for re-invasion.     

Long-term movements of self-marked caddisfly larvae (Trichoptera: Sericostomatidae) in a California coastal mountain stream

1. Over 140 000 larvae of the case-building caddisfly Gumaga nigricula were self-marked as they incorporated glitter into small portions of their cases while reared in streamside troughs. These marked individuals were released into stream pools and their movements monitored in the dry season, when base flow was low and no spates occurred, and in the wet season when base flow was high and several spates occurred. 2. Of the 9,000–10 000 larvae released in each of two stream pools in the dry season, 4–20% (i.e. 377–1817 marked individuals) were observed on three sampling dates (4, 11 and 24 d after release). Most larvae (87–93%) remained within 4 m up- or downstream of the release line after 24 d. No larvae were found outside of the release pools, even after 37 d. 3. Of the > 120 000 larvae released in one stream pool near the beginning of the wet season, 408 larvae were recaptured 130–167 d later, a period that included 30 days of high flow associated with six spates. Estimated survivorship over this period was 0.7–6.2%; there was no relationship between survival and larval size at release. Most (75%) recaptured larvae were found in the pool where they were originally released. The remaining larvae were found downstream of the release pool. Larvae had generally dispersed only a short distance downstream of the release pool (median = 18 m, maximum = 222 m). In addition, four marked pupae were later found 436 m downstream of the release pool. 4. These results illustrate the sedentary nature of larval G. nigricula as well as the important role that high flow events play in larval mortality and dispersal. These case-building larvae move very little during low flow periods, even when food resources appear limiting. In contrast, the frequency and distance of larval dispersal are much greater during periods with high flow. 5. Our observations for G. nigricula support previously published inferences that larval dispersal within a stream can be limited for some aquatic insects. However, our observations also suggest that, even for a relatively sedentary species like G. nigricula, larval dispersal during periods with high flow may contribute significantly to gene flow within a stream reach.     

The effects of cannibalism on Amazonian poison frog egg and tadpole deposition and survivorship in Heliconia axil pools

This study investigated the influence of cannibalism on egg and larval mortality, and on the deposition strategies of adults, in a tropical anuran breeding in very small leaf axil pools. Patterns of egg and tadpole deposition and mortality in the Amazonian poison frog, Dendrobates ventrimaculatus, were monitored in rainforest near Pompeya in Sucumbios Province, Ecuador. Oviposition and tadpole deposition typically ocurred in leaf axils of Heliconia plants. Pools typically received more than one oviposition. Egg survivorship was low, and significantly lower when eggs were deposited in pools with large tadpoles, indicating that cannibalism is an important source of mortality. Tadpole survivorship was also associated with the presence of other tadpoles: most pools ended with only one surviving tadpole, regardless of the number of tadpoles deposited in the pool. Egg deposition was signifcantly less likely for pools that had a tadpole in them, suggesting that adults can detect the presence of tadpoles and avoid ovipositing in pools that contain them. This hypothesis was tested with a series of pool choice experiments, which revealed that D. ventrimaculatus avoid placing either eggs or tadpoles into a pool which contains a large tadpole. Several hypotheses which could explain multiple deposition in this species are discussed. Received: 14 September 1998 / Accepted: 25 January 1999     

Feeding behaviour, food consumption, and growth efficiency of hemiclonal and parental tadpoles of the Rana esculenta complex

1. Clonally reproducing species are often assumed to lack sufficient genetic variability to evolve specific local adaptations to cope with environmental perturbation and competition from sexual species. Yet, many asexuals are extremely successful judged by abundance and wide range, suggesting high competitive abilities in resource exploitation.
2. In this study, food use and its effects on larval growth in a water frog system consisting of the two parental sexual species, Rana lessonae (Camerano 1882) and Rana ridibunda (Pallas 1771), and three different coexisting hemiclones of their hybrid, Rana esculenta (Linnaeus 1758) were investigated.
3. R. esculenta tadpoles spent 18·6% more time feeding than did tadpoles of either parental species, but feeding time was not affected by interspecific mixture.
4. R. esculenta tadpoles consumed 50·8% more food over the whole test period than did tadpoles of the two parental species.
5. R. esculenta tadpoles exhibited higher growth rates than did tadpoles of either parental species.
6. R. lessonae tadpoles had the highest and R . ridibunda tadpoles the lowest growth efficiencies with the R. esculenta tadpoles ranging between the two parentals.
7. The results obtained indicate that hemiclonal hybridogenetic R . esculenta tadpoles display significant phenotypic variation among coexisting hemiclones as well as out-perform tadpoles of the parental sexual species R. lessonae and R . ridibunda. The primary mechanism for success of the hybrid tadpoles is probably behavioural, through increased feeding time and food consumption, and not physiological via growth efficiency.     

Prey behaviour and size-selective predation by fish

SUMMARY 1. We investigate the role of differential activity of chiro-nomids as an explanation for the size selection of small larvae by fish.
2. In the laboratory, pumpkinseed sunfish (Lepomis gibbosus L.) selectively consumed large larvae of Chironomus tentans Fab. when no tube-building materials were available. Small larvae were selectively consumed when a mud substrate was provided but there was no difference in predation rates on large and small larvae in sand.
3. Small larvae spent more time out of their tubes than large larvae in the presence of fish, which may explain the selection for small larvae in mud. Large larvae apparently compensated for decreased foraging activity in the presence of fish by increasing activity when fish were absent. Visibility of large larvae inside tubes may account for their increased mortality in sand.
4. Our results suggest that differential activity is important in explaining the size-selective mortality observed in the field.     

Habitat distribution and body size in rain-pool dwellers

Rain-pools differ from oceanic islands, essentially, in being ephemeral. Ability to disperse and reproduce is therefore a special priority among inhabitants.
Pupal exuviae of a principal inhabitant, Chironomus imicola , were collected from pools in tropical Africa. Length of pupal skin is positively related both to flight duration and ovule number in adult chironomids. Hence length of pupal skin can be related to fitness in this temporary pool dweller.
Predictably, therefore, remote pools are inhabited by large individuals while those in clusters have more small forms.
That duration of the habitat also influences body size is demonstrated by Polypedilum vanderplanki. These larvae are able to survive dry periods and therefore experience the habitat as permanent. In contrast to C. imicola, P. vanderplanki responds to isolation with a disproportionate number of small flies.
In addition to these differences in average size, variance in body size is affected by isolation of the habitat. Comparison with progeny of a single female shows increased variability to be determined not only by habitat location but also to be an inherent characteristic of animals perceiving the habitats as ephemeral.     

The role of periphyton abundance and quality in the microdistribution of a stream grazer, Helicopsyche borealis (Trichoptera: Helicopsychidae)

SUMMARY. 1. A series of laboratory and field experiments was performed to determine if the preference of larvae of Helicopsyche borealis (Trichoptera: Helicopsychidae) for exposed rock surfaces in streams was related to patchiness of periphyton food.
2. At low current velocities in the laboratory larvae preferred food-saturated as opposed to food-depleted portions of substrata and drifted off the substratum in response to low food levels.
3. When offered a choice of three potential foods—a diatom, a green filamentous or a blue-green filamentous alga—larvae showed no preference.
4. Larval densities on artificial subtrata in field experiments were highest in areas of high algal chlorophyll a .
5. In laboratory experiments more adults emerged from cultures containing green algae or diatoms than cultures with blue-green algae or bacteria alone.
6. Periphyton quality was not as important as abundance in controlling H. borealis microdistribution. By selecting exposed surfaces of rocks, H. borealis larvae place themselves in the microhabitat most likely to contain both abundant and high quality food patches.     

Biological warfare in the garden pond: tadpoles suppress the growth of mosquito larvae

Abstract. 1. Although tadpoles and mosquito larvae may compete for scarce resources in natural freshwater systems, the mechanisms involved in such competition remain largely unstudied.
2. Replicated artificial ponds were set up to examine the role of pathogenic interference (water-borne growth inhibitors) in two tadpole–mosquito systems from south-eastern Australia. One system comprised taxa that are commonly sympatric in freshwater ponds (tadpoles of Limnodynastes peronii and larvae of Culex quinquefasciatus ) while the other comprised species that co-occur in brackish water ponds (tadpoles of Crinia signifera and larvae of Ochlerotatus australis ).
3. Water that had previously contained tadpoles suppressed the rates of survival and pupation of mosquito larvae in both systems. Fungicide reduced or eliminated this effect, suggesting that the growth inhibitors may be fungal organisms (possibly the yeast Rhodotorula glutinis ) from tadpole faeces. Fungicide also enhanced growth rates of tadpoles.
4. These results suggest that interference competition between tadpoles and mosquito larvae is mediated by other organisms in some ecological systems.     

Context-dependent aggregation in Common Frog Rana temporaria tadpoles: influence of developmental stage, predation risk and social environment

1. This study examines the aggregation behaviour and activity of larvae of the Common Frog Rana temporaria in relation to the early social environment, ontogeny and the presence of chemical cues from a predatory fish to address three main questions: (i) Does previous social interaction influence aggregation behaviour in later developmental stages? (ii) To what extent does aggregation behaviour depend upon the risk level perceived by the individual? (iii) Does aggregation behaviour change through ontogeny?
2. Tadpoles were reared from eggs either in small groups or in complete isolation. In relatively early stages of development, tadpoles showed no preference for the side of the test container containing siblings over the side containing no larvae regardless of the social context experienced (isolation or contact with siblings).
3. The presence of chemical cues from a potential predator did not trigger the aggregation behaviour of tadpoles, but it had a remarkable effect on their activity and spatial distribution. Tadpoles exposed to water preconditioned by a predator spent significantly less time swimming and avoided the central area of the test container more frequently than did controls exposed to unconditioned water.
4. Tadpoles were more active, avoided the central section and associated preferentially with conspecifics (siblings) at later stages of development regardless of the social conditioning they had previously experienced.
5. Individuals reared in groups were twice as active as individuals reared in isolation. This suggests that the early social environment experienced by larvae can influence future behaviour and thereby growth and development rates.
6. The expression of conspecific attraction is probably linked to an ontogenetic shift in larval behaviour. However, reduced activity, rather than aggregation, appears to be the basic antipredator mechanism in larval Common Frog.     

Performance of Five Food Regimes on Anopheles gambiae Senso Stricto Larval Rearing to Adult Emergence in Insectary

Background

Rearing of Anopheles gambiae s.s mosquitoes in insectary with quality cheap food sources is of paramount importance for better and healthy colony. This study evaluated larval survival and the development rate of aquatic stages of An.gambiae s.s under five food regimes; tetramin fish food (a standard insectary larval food), maize pollen, Cerelac, green filamentous algae and dry powdered filamentous algae.

Methods

Food materials were obtained from different sources, cerelac was made locally, fresh filamentous algae was taken from water bodies, dry filamentous algae was ground to powder after it was dried under shade, and maize pollen was collected from the flowering maize. Each food source type was used to feed three densities of mosquito larvae 20, 60, and 100 in six replicates each. Larval age structure was monitored daily until pupation and subsequently adult emergence. Tetramin was used and taken as a standard food source for An. gambiae s.s. larvae feeding in Insectary.

Results

Larval survivorship using maize pollen and Tetramin fish food was statistically insignificant (P = 0.564). However when compared to other food regime survivorship was significantly different with Tetramin fish food performing better than cerelac (P<0.001), dry algae (P<0.001) and fresh algae (P<0.001). The pupation rates and sex ratio of emerging adults had significant differences among the food regimes.

Conclusion

The findings of this study have shown that maize pollen had closely similar nutritional value for larval survivorship to tetramin fish food, a standard larvae food in insectary. Further studies are required to assess the effect of food sources on various life traits of the emerged adults.     

Feeding by omnivores increases food available to consumers

Consumers are usually thought of as negatively affecting producers, but they can affect them positively by releasing nutrients (nutrient regeneration). The net effects of consumers on producers should depend on the balance between the effects of consumption and nutrient regeneration. In aquatic habitats, nutrient regeneration by consumers may increase microbial activity on leaf detritus as well as algal production, which in turn may stimulate further nutrient release and benefit herbivores or detritivores by increasing food quantity or quality. Omnivores can regenerate nutrients from animals, algae and detritus, creating diverse nutrient pathways. Many tadpoles are omnivores, and their nutrient regeneration may be important in aquatic food webs. To reveal the nutrient pathways created by tadpoles and examine whether omnivorous tadpoles can have positive effects on producers and consumers, we experimentally examined the effects of nutrient regeneration by three densities of tadpoles on primary producers, leaf litter, and other consumers in tank mesocosms. Tadpole exclosures were placed inside each mesocosm, allowing us to separate direct consumption effects from indirect nutrient regeneration effects. Nutrient regeneration caused by the herbivorous and carnivorous feeding activities of tadpoles positively affected rates of production of benthic algae, phytoplankton, and herbivorous benthic chironomid larvae, and rates of mineralization of leaf litter. The increased production of benthic algae and chironomid larvae was consumed by the tadpoles themselves, leaving no net change in the standing biomass of these resources. Our experiment thus demonstrated that omnivores created complicated nutrient pathways and accelerated rates of primary production and growth rates of other consumers, leading to increased rates of food availability to the omnivores themselves. Interactions of this nature may be common in many systems and could strongly moderate the effects of consumers on their resources and each other.     

Feeding ecology of Macrobrachium borelli (Nobili) (Decapoda: Palaemonidae) in the flood valley of the River Paraná, Argentina

The feeding habits and selectivity of Macrobrachium borelliiwere studied by examining the stomach content of specimens from anox-bow lake across one year. M. borellii isomnivorous-carnivorous, feeding largely on members oflittoral-benthic communities. The bulk of the stomach content wasformed by oligochaetes, dipteran larvae, and a variety of organismsranging from algae to palaemonids. Copepods and cladocerans were analternative food source in winter, at low-water, when macrophytes haddeclined. Oligochaetes and dipteran larvae were positively, algae andmicrocrustaceans negatively selected. This revised version was published online in July 2006 with corrections to the Cover Date.     

Oviposition site selection by mosquitoes is affected by cues from conspecific larvae and anuran tadpoles

Abstract The oviposition site that a female mosquito selects will influence the fitness of her larvae. We conducted a series of artificial pond experiments to compare the oviposition responses of two species of mosquitoes with the presence of tadpoles, conspecifics and chemical cues from these organisms. The two mosquito species differ markedly in larval ecology. The larvae of one species, Culex quinquefasciatus, co‐occur with numerous freshwater organisms, including tadpoles of Linmodynastes peronii (the striped marsh frog). Larvae of the other mosquito, Ochlerotatus australis, inhabit small brackish rock ponds where the main potential competitors are tadpoles of Crinia signifera (the common eastern froglet). In field trials, females of both mosquito species oviposited significantly more often in water that contained (or had previously contained) conspecific larvae. However, these superficially similar responses were mediated via different pathways: fungicide abolished the response by C. quinquefasciatus but not by O. australis. The two mosquito species also responded differently to cues associated with syntopic tadpoles. The presence of tadpoles did not influence oviposition by C. quinquefasciatus, but O. australis oviposited less often if tadpoles were present. These interspecific differences in oviposition behaviour may be adaptive to differences in larval ecology: competition with tadpoles is likely to be more significant for O. australis than for C. quinquefasciatus. Our findings thus support the hypothesis that mosquitoes oviposit selectively to avoid potential anuran larval competitors.