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.

Population phenology of whitefringed weevil, Graphognathus leucoloma (Coleoptera: Curculionidae), in pasture in a Mediterranean-climate region of Australia

1991 ◽  
Vol 81 (3) ◽  
pp. 283-289 ◽  
Author(s):  
J. N. Matthiessen
Keyword(s):  
Mediterranean Climate ◽  
Larval Growth ◽  
Winter Period ◽  
Larval Recruitment ◽  
Climate Region ◽  
Spring Period ◽  
First Instar ◽  
Late Instar ◽  
One Year ◽  
The One

AbstractIn undisturbed annual pasture in a Mediterranean-climate region of Australia adults of the whitefringed weevil, Graphognathus leucoloma (Boheman), were present from summer to early winter (December–June), with upsurge in numbers of first instar larvae only occurring after the rains began in April. The G. leucoloma population was predominantly first instar larvae in high abundance throughout the winter period (May–August). Larval growth, with high mortality, occurred in the spring period (September–January). The survival of eggs during the dry summer when adults were most abundant, although only at times of unseasonal rainfall, indicated that low larval recruitment at that time resulted primarily from the absence of high-quality legume food essential for oogenesis. It was inferred that most larvae arose from heavy oviposition by the few adults present in autumn when rainfall germinated annual legumes. A steady year-round abundance of late-instar larvae indicated that not all individuals completed their development in the one year.

Predation of Indianmeal Moth Larvae by Lyctocoris campestris (F.) (Hemiptera: Anthocoridae) in Different Stored Commodities

1997 ◽  
Vol 32 (3) ◽  
pp. 271-280 ◽  
Author(s):  
R. L. Meagher ◽  
L. A. Locke
Keyword(s):  
Functional Response ◽  
Prey Density ◽  
Plodia Interpunctella ◽  
Type Ii ◽  
Indianmeal Moth ◽  
Whole Wheat ◽  
Late Instar ◽  
Response Equation ◽  
Predation Rates ◽  
Type Ii Functional Response

Predation rates for the anthocorid predator Lyctocoris campestris (F.) against varying densities of late-instar Plodia interpunctella (Hübner) were compared in whole corn, whole wheat, or rolled oat stored commodities. More prey were attacked in corn and wheat than in oats, and female predators generally fed on more larvae than did male predators. Predation increased with an increase in prey density. This relationship was best described by a Type II functional response equation. Our results suggest that commodity type affects the number of prey attacked by this predator.

SILKING BEHAVIOR OF THE GYPSY MOTH, PORTHETRIA DISPAR

1967 ◽  
Vol 99 (11) ◽  
pp. 1145-1149 ◽  
Author(s):  
David E. Leonard
Keyword(s):  
Gypsy Moth ◽  
Larval Instar ◽  
Diel Periodicity ◽  
First Instar ◽  
Porthetria Dispar ◽  
Late Instar

AbstractAfter feeding, gypsy moth larvae construct a silk mat (resting mat) on which they remain. Prior to molting, this mat is reinforced, or a new, dense mat is constructed (molting mat). Late in the last larval instar, a sparse cocoon is constructed. When larvae are starved, a shift in behavior is noted, with increased locomotion, irritability, and the trailing of a strand of silk as larvae wander. First-instar larvae, quiescent and anchored on resting mats, are not readily induced to spin down on silk threads; hence are not readily dispersed by wind. Hungry first-instar larvae, more apt to be spinning down, are presumed to be more readily dispersed by wind. Larvae which undergo an additional instar have a longer prefeeding phase and might be more readily dispersed than "normal' larvae. The effects of hunger may also cause the shift in diel periodicity of mid- and late-instar larvae, resulting in some dispersal of these larvae away from areas where food will be depleted.

Effects of an Experimental Lake Acidification on Zooplankton Feeding Rates and Selectivity

1990 ◽  
Vol 47 (4) ◽  
pp. 772-779 ◽  
Author(s):  
Michael E. Sierszen ◽  
Thomas M. Frost
Keyword(s):  
Population Level ◽  
Plankton Community ◽  
Lake Acidification ◽  
System Level ◽  
Phytoplankton Species ◽  
Fine Scale ◽  
Important Process ◽  
Selective Feeding ◽  
Feeding Rates ◽  
Integrative System

Although the changes in plankton community composition that result from lake acidification have been documented, little is known about processes that accompany these changes. Here we report investigations on an important process, zooplankton herbivory, in an experimentally acidified lake. Acidification from pH 6.2 to 5.2 has not directly impaired the ability of several major taxa to gather food. Acidification may indirectly affect selective feeding behavior, through changes in the relative abundance of phytoplankton species. Dramatic shifts in population-level grazing were not reflected in overall community herbivory, because of complementary changes in populations in the reference and treatment lake basins. Hence, integrative system-level functions may be poorer indicators of perturbation than specific, fine-scale processes.

scholarly journals Occurrence, development and gall polymorphism of Harmandiola cavernosa (Rübs.) (Diptera, Cecidomyiidae)

2010 ◽  
Vol 58 (2) ◽  
pp. 235-258 ◽  
Author(s):  
Jaroslav Urban
Keyword(s):  
Gall Midge ◽  
Mortality Factors ◽  
The Third ◽  
First Instar ◽  
Insect Predators ◽  
The Creation ◽  
Forest District

A gall midge Harmandiola cavernosa (Rübs.) is the second most frequent Cecidomyiidae species on Po­pu­lus tremula in the CR. In 2007 and 2008, it occurred very abundantly in Forest District Bílovice nad Svitavou, Training Forest Enterprise Masaryk Forest in Křtiny (former Brno-venkov District). Imagoes occurred there at the end of April and at the beginning of May. Galls grew up as early as at the end the first week in May. The formation of galls is mainly indicated by larvae of the first instar and partly larvae of the second instar. Larvae of the third instar did not participate in the creation of galls. Mature galls were on average 5.4 mm long, 4.8 mm wide and 4.7 mm high showing an inner chamber of an ave­ra­ge length 2.4 mm and width 1.4 mm. Larvae abandoned galls from the end of May until mid-July. On average, 44% larvae completed successfully their development in galls. About 26% larvae were killed by insect parasitoids (mainly Torymus quercinus Boh.) and then same proportion of larvae died without any apparent exogenous causes). Insect predators and birds killed 4% larvae on average. It has been found that mortality factors markedly participated in the size, morphological, anatomical and physiognomic differentiation of galls. Gall polymorphism was analysed in detail in the paper. Galls significantly unfavourably affected the size of leaves and thus also photosynthesis.1

Biology and host specificity of the Chondrilla crown moth, Oporopsamma wertheimsteini (Rebel) (Lepidoptera: Tortricidae)

1977 ◽  
Vol 67 (4) ◽  
pp. 619-625 ◽  
Author(s):  
S. Hasan ◽  
A. J. Wapshere
Keyword(s):  
Biological Control ◽  
Host Specificity ◽  
Biological Control Agent ◽  
Control Agent ◽  
Plant Family ◽  
Collar Region ◽  
First Instar ◽  
Late Instar ◽  
Safety Studies ◽  
Chondrilla Juncea

AbstractThe tortricid moth Oporopsamma wertheimsteini (Rebel) is a potential biological control agent of Chondrilla juncea, which is a serious introduced weed in Australia. The biology of the moth was studied on wild C. juncea growing in Azerbaidzhan (Iran). It has one generation per year and undergoes two periods of diapause, aestivating as a pupa and hibernating as an egg. The larvae live in cases attached to and feeding on the collar region of C. juncea and may destroy plants with thin stems. Larval infestations are common on C. juncea growing in sandy soils. The braconid Chelonus asiaticus Telenga was recorded as a larval parasite. Host specificity assessment by laboratory tests in France, in which trimmed crowns of various Compositae were exposed to late-instar larvae, suggested that they had a broader host range within that plant family than would be desirable in an organism to be used for biological control. However, tests under both field and glasshouse conditions in Iran indicated that the first-instar larvae select only Chondrilla juncea as hosts. The species was therefore introduced into Australia under quarantine for further host-safety studies.

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.

scholarly journals Plastic responses in the coral Pocillopora acuta to extreme low-light conditions with and without food provision

2021 ◽  
Vol 168 (7) ◽  
Author(s):  
Jenny Fong ◽  
Rosa Celia Poquita-Du ◽  
Peter A. Todd
Keyword(s):  
Species Differences ◽  
Light Level ◽  
Ambient Light ◽  
Light Conditions ◽  
Feeding Rates ◽  
Low Light ◽  
Reef Environment ◽  
Ambient Light Level ◽  
Related Stress ◽  
Plastic Responses

AbstractThis study examines phenotypically plastic responses in Pocillopora acuta collected from a highly urbanized reef environment to extreme low-light conditions. While among-species differences in how corals cope with low light are well documented, much less is known about within-species responses. It also remains unclear how extreme low light and provision of food may interact and influence coral physiology. Clonal fragments from six colonies (genotypes) of P. acuta were subjected to two light treatments with mean midday irradiances of 4 and 40 μmol photons m−2 s−1 photosynthetically active radiation (PAR), representing just 0.5 and 5% ambient light level, and were either fed with zooplankton or not fed for nine days. Corals maintained in 4 PAR had lower endosymbiont density but higher cellular chlorophyll a concentration than those in 40 PAR. Feeding rates were similar in both light treatments and had no significant effects on endosymbiont density and chlorophyll a concentrations. While genotypes varied in the level of phenotypic plasticity expressed for both photoacclimation and heterotrophy, most displayed similar directions in their responses, indicating photoacclimation in P. acuta is broadly predictable. Our study demonstrates that P. acuta from Singapore is able to acclimate to very low-light conditions by adjusting their photophysiology, providing additional evidence that this species is resilient to urbanization-related stress.

Functional response analysis of size-selective predation by the notonectid predator Anisops deanei (Brooks) on Daphnia thomsoni (Sars)

1984 ◽  
Vol 35 (6) ◽  
pp. 725 ◽  
Author(s):  
JG Reynolds ◽  
MC Geddes
Keyword(s):  
Functional Response ◽  
Prey Type ◽  
Size Class ◽  
Response Analysis ◽  
Response Curves ◽  
Selective Predation ◽  
Size Classes ◽  
Effective Predator ◽  
Typical Type ◽  
Predation Rates

The functional response of A. deanei to uncrested D. thomsoni was calculated by predation experiments in the laboratory. A. deanei produced typical type 11 functional response curves when presented with increasing densities of any given size-class of D. thomsoni Predation rates were highest for small size-classes and decreased for prey sizes above 2 mm In mixed-prey populations A deanet showed a greater preference towards the smaller, preferred prey than was predicted from the angle-prey-type expenments, thus demonstrating an exercise of choice by the predator. Crests developed by the smaller, preferred size-classes of D. thomsoni did not act as effective anti-predator mechanisms against A. deanei which may be able to remam an effective predator on crested populations of D. thomsonl.

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