Larval Mosquitoes as Vulnerable Prey: Chaoborus Predation

1989 ◽  
Vol 46 (9) ◽  
pp. 1642-1650 ◽  
Author(s):  
J. C. Helgen
Keyword(s):  
Daphnia Pulex ◽  
Choice Experiments ◽  
Distinct Difference ◽  
Prey Choice ◽  
Temporary Wetlands ◽  
Aedes Vexans ◽  
Selective Force ◽  
Chaoborus Americanus ◽  
Predation Rates

The vulnerability of instar I and II larvae of the mosquito Aedes vexans as prey for Chaoborus americanus is much greater than that of the small coexisting prey, Daphnia pulex. Predation on Aedes larvae could reduce Aedes populations in overlapping habitats, and be a selective force in driving Aedes to lay eggs in muds of more temporary wetlands. Predation rates are great (7–25∙d−1) and ingestion times are rapid (0.8–6 s) on Aedes instars I and II. In prey choice experiments, Chaoborus strongly prefers Aedes I over small Daphnia. An Aedes diet promotes growth of Chaoborus at least as well as a Daphnia diet. Larval Aedes behaviors show a distinct difference between the first two and last two instars. Aedes swimming speeds and swimming distances increase with each instar, but when disturbed, the first two instars significantly reduce their swimming distances. Calculated prey vulnerabilities, based on swimming speeds and reciprocal ingestion times, suggest a much greater vulnerability for Aedes I and II than that for small (0.8 mm) Daphnia or for Aedes III and IV (4.6–6.2 mm).

Vertical distributions and zooplankton predation in a small temperate pond

1981 ◽  
Vol 59 (9) ◽  
pp. 1720-1725 ◽  
Author(s):  
Guy E. Melville ◽  
Edward J. Maly
Keyword(s):  
Daphnia Pulex ◽  
Predation Rate ◽  
Invertebrate Predation ◽  
Chaoborus Americanus ◽  
Vertical Distributions ◽  
Zooplankton Communities ◽  
The Impact ◽  
Predation Rates

Depth-specific sampling in a small Quebec pond between April and October 1977 revealed that instars of Daphnia pulex less than 1.41 mm in length and instars of Diaptomus leptopus greater than 0.64 mm in length consistently had vertical distributions which were different from those of late instars of their predator Chaoborus americanus. Experiments were done to determine to what extent these distributions affected the rate of predation by Chaoborus. Vertical and horizontal 25-L enclosures, 1.4 m long, and 2.5-L enclosures, all containing Chaoborus–prey pairs, were introduced into a pond for 3-day periods weekly from July to September. Predation rates in vertical enclosures were considerably lower than those in small and horizontal enclosures. These results suggest that distributions of Diaptomus and Daphnia in vertical enclosures significantly reduce predation on them by Chaoborus. In horizontal and small enclosures where overlap of predator and prey was increased, predation rate of Chaoborus was higher. Results are discussed in relation to the impact of invertebrate predation on zooplankton and the structure of zooplankton communities.

Inter- and Intra-specific Variability in the Response of Zooplankton to Acid Stress

1985 ◽  
Vol 42 (11) ◽  
pp. 1749-1754 ◽  
Author(s):  
Edmund E. Price ◽  
Michael C. Swift
Keyword(s):  
Natural Populations ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Intraspecific Variability ◽  
Early Summer ◽  
Low Ph ◽  
Acid Sensitivity ◽  
Chaoborus Americanus ◽  
Acute Bioassays ◽  
Mesocyclops Edax

We measured the toxicity of sulfuric acid to natural populations of Daphnia pulex, D. galeata mendotae, Simocephalus serrulatus, Mesocyclops edax, Chaoborus americanus, and C. punctipennis. Organisms were collected in the spring and fall from acidic (pH 5.4) and circumneutral (pH 6.3–7.5) ponds, and their response to low pH was compared in 48- or 96-h acute bioassays. Based on 48- and 96-h LC50, cladocerans were most susceptible to acid stress, followed by Mesocyclops and Chaoborus larvae. Simocephalus was the most tolerant cladoceran, followed by D. pulex then D. galeata mendotae. Daphnia populations tested in the spring or early summer were more tolerant of low pH than those tested in the fall. Mesocyclops edax from an acid pond were more tolerant than those from a neutral pond. The response of the two Chaoborus species to low pH were quite similar; their 96-h LC50 (2.00, 2.09) was two pH units lower than those of cladocerans and one pH unit lower than that of M. edax. Our data demonstrate interspecific variability in acid sensitivity and suggest intraspecific variability due to habitat and season.

The influence of benthic tundra pond vegetation and prey behavior on Zooplankton predation by the flatworm Mesostoma lingua

1985 ◽  
Vol 63 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Hugh J. MacIsaac ◽  
Thomas C. Hutchinson
Keyword(s):  
Daphnia Pulex ◽  
Chironomus Riparius ◽  
Alternative Prey ◽  
Prey Behavior ◽  
Predation Rates ◽  
Branchinecta Paludosa

Experiments were conducted at the Smoking Hills and Tuktoyaktuk, N.W.T., to determine if Mesostoma lingua, a common pond inhabitant, preys selectively on co-occurring Zooplankton, and whether predation rates are affected by the presence of pond vegetation. Experiments were conducted in 250-mL containers at the sites. Mesostoma fed heavily on Daphnia pulex and Chironomus riparius, but not on Branchinecta paludosa or Diaptomus arcticus. The presence of alternative prey led to significant reductions in Daphnia predation rates, while the presence of the pond plants Cladophora insignis and Drepanocladus aduncus, which provide shelter and cover, significantly increased predation rates. The advantage of the moss and algal habitat was largely to the predator.

The impact of two Chaoborus species on a zooplankton community

1990 ◽  
Vol 68 (5) ◽  
pp. 981-985 ◽  
Author(s):  
Neil A. MacKay ◽  
Stephen R. Carpenter ◽  
Patricia A. Soranno ◽  
Michael J. Vanni
Keyword(s):  
Chlorophyll A ◽  
Daphnia Pulex ◽  
Zooplankton Community ◽  
Chlorophyll A Concentration ◽  
Chaoborus Flavicans ◽  
Chaoborus Americanus ◽  
Diaptomus Oregonensis ◽  
Herbivore Responses ◽  
The Impact

The responses of a zooplankton community to Chaoborus predation were studied in large in situ mesocosms in Peter Lake. Chaoborus flavicans, the native chaoborid, significantly reduced the density of the dominant grazer, Daphnia pulex, in relation to controls that lacked Chaoborus. Chaoborus americanus, a species found only in fishless bogs, reduced Da. pulex densities far more than the chaoborid found in Peter Lake, C. flavicans. Chaoborus americanus also significantly reduced the dominant copepod, Diaptomus oregonensis, in relation to both the control and the C. flavicans treatment. Chlorophyll a concentration did not differ among treatments, indicating that herbivore responses could not be explained by changes in food levels. Our results show that Chaoborus predation can greatly affect a zooplankton community, especially daphnids.

Selective predation on cladocerans by common pond insects

1983 ◽  
Vol 61 (4) ◽  
pp. 879-886 ◽  
Author(s):  
Scott D. Cooper
Keyword(s):  
Light Conditions ◽  
Selective Feeding ◽  
Feeding Rates ◽  
Selective Predation ◽  
Anax Junius ◽  
First Instar ◽  
Chaoborus Americanus ◽  
Late Instar ◽  
Insect Predators ◽  
Predation Rates

A variety of common pond insects was presented with a mixture of different size classes of Daphnia magna or different sizes of Daphia pulex, Moina affinis, and Ceriodaphnia sp. in predation trials. Juvenile Belostoma flumineum and most instars of Notonecta undulata and Anax Junius fed at the highest rates on the largest available cladoceran prey, and late-instar Buenoa corfusa fed at the highest rates on prey between 0.8 and 2.0 mm in length. Predation rates of instar IV Chaoborus americanus larvae were highest on Daphnia < 1 mm in length, and lowest on Daphnia > 2 mm in length. First-instar Chaoborus larvae did not eat cladocerans in these trials. The size-selective feeding patterns exhibited by Notonecta adults and late-instar Anax were similar in the light and dark, although overall feeding rates were depressed in the dark. Buenoa, on the other hand, only exhibited size-selective feeding in the light. The results indicate, however, that all of these insect predators can feed in the dark. Predation rates for late-instar Chaoborus larvae were unaffected by light conditions or the presence of filamentous algae. Chaoborus larvae were readily eaten by late-instar Notonecta and Anax.

scholarly journals Selective advantage conferred by resemblance of aposematic mimics to venomous model

2017 ◽  
Vol 17 (3) ◽  
Author(s):  
Frederico Gustavo Rodrigues França ◽  
Vívian da Silva Braz ◽  
Alexandre Fernandes Bamberg de Araújo
Keyword(s):  
Selective Advantage ◽  
Coral Snake ◽  
Selective Force ◽  
Exact Test ◽  
Central Brazil ◽  
Body Regions ◽  
Different Color ◽  
And Behavior ◽  
Model Affect ◽  
Predation Rates

Abstract Mimicry is an excellent example of how natural selection can act on color, morphology, and behavior of species. Herein we assess predation rates on coral snake mimics in Central Brazil, a region with many mimics but only a single model, to answer the following questions: (i) Do predators avoid attacking coral snake mimics? (ii) Does the degree to which mimics resemble their venomous model affect the frequency of predator attacks? (iii) Do predators attack different body regions in mimics with different color patterns? Our experiment was conducted in the Chapada dos Veadeiros National Park, in the municipality of Alto Paraíso de Goiás, state of Goiás, Brazil. To evaluate predation rates on the different mimic patterns, we made 2,400 clay snake replicas using pre-colored nontoxic plasticine and distributed them in open savanna landscapes within the park. A total of 164 (6.83%) replicas were attacked by predators of snakes. Among these attacks, 121 were attacks by birds, and 43 were attacks by carnivorous mammals. Logistic regression and Fisher’s exact test indicated that replicas with red, white, and black coloration are less likely to be attacked than were grey replicas, and coral snake replicas were attacked more often at the “head” end. Also, the greater the similarity to the pattern of venomous coral snakes, the rarer the attack on the replica. Our study underscores the strong selective force that protects coral snake mimics from predators. Our findings reinforce resemblance to the model as an extremely effective strategy in a complex natural system with only one model and numerous mimics.

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