Клопы: водомерки, влияние высыхания

Клопы

Клопы: водомерки, влияние высыхания.

Volume 23 Issue 4 Page 370

Tetsuo Harada

Abstract.1. Adults of Aquarius paludum inhabit both temporary and permanent water surfaces; Gerris latiabdominis lives only in temporary habitats. To clarify whether adults of both species stay in position or fly when habitats dry up, overwintered adults of A. paludum and G. latiabdominis collected in spring were reared under one of the following four conditions: (A) on water with sufficient food, (B) on water, starved, (C) on wet paper with sufficient food, (D) on wet paper, starved. All rearings were at LD15.5:8.5h, 20+2шC, resembling natural conditions for April to June.

2. Females of A. paludum in group C had lower fecundity than the control group A and some stopped laying eggs. When a water surface was restored, females that had entered reproductive diapause began to lay eggs again. In contrast, females of G. latiabdominis continued to lay eggs even when reared on damp paper.

3. Adults of A. paludum lived longer and adopted diapause posture with high frequency when starved and reared without a water surface. There were, however, no significant differences in the longevity or in the number of adults showing diapause posture between groups A and D of G. latiabdominis.

4. Females of A. paludum collected in the middle of May had more mature oocytes (mean: 20.8) than females of G. latiabdominis (mean: 8.0), and most had histolysed their indirect flight muscles; most females of G. latiabdominis had retained their flight muscles and flew readily.

5. When water surfaces dry, with food shortage, adults of A. paludum may survive in place for a relatively long time until the water surface returns. Adults of G. latiabdominis may fly to other water surfaces and reproduce without delay.

Клопы: Notonecta, питание.

Volume 23 Issue 3 Page 246-252 - September 1998

BLAUSTEIN LEON

1. The impact of the predator, Notonecta maculata, on invertebrate community structure was investigated by a combination of a natural pool survey, an outdoor artificial pool experiment, and a laboratory prey preference experiment.

2. In a survey of forty natural pools in the Negev Desert, Israel, pelagic/neustonic species richness and overall species richness, but not benthic species richness, were negatively associated with N. maculata density.

3. In the artificial pool experiment, in which the presence or absence of Notonecta was manipulated, Notonecta caused a reduction in the richness of species colonizing the pools. Notonecta strongly reduced densities of the pelagic dipterans, Culiseta longiareolata (often 100% reduction of later-instar larvae and pupae) and ephydrids. Fewer Culiseta egg rafts were found in Notonecta pools, indicating that part of the observed reduction of Culiseta is not due to consumption of Culiseta larvae by Notonecta, but to habitat selection by ovipositing Culiseta females in response to risk of predation by Notonecta. Notonecta did not affect densities of (benthic) chironomids or the small cladoceran, Ceriodaphnia cf. quadrangula. Laboratory assessments of selectivity by Notonecta for the various prey matched patterns found in the field experiment.

4. This work provides strong evidence that N. maculata is an important organizer of community structure: it strongly reduces or even eliminates larger pelagic or neustonic species, but does not affect densities of small or benthic species.

Клопы: Naucoridae

Authors: Sites-RW Willig-MR

Title: Microhabitat Associations of 3 Sympatric Species of

Naucoridae (Insecta, Hemiptera)

Source: ENVIRONMENTAL ENTOMOLOGY

1991, Vol 20, Iss 1, pp 127-134

Language: English

Document type: Article

Addresses:

TEXAS-TECH-UNIV, DEPT AGRON HORT & ENTOMOL, LUBBOCK, TX 79409,

USA

TEXAS-TECH-UNIV, DEPT BIOL SCI, ECOL PROJECT, LUBBOCK, TX

79409, USA

TEXAS-TECH-UNIV, MUSEUM, LUBBOCK, TX 79409, USA

Author keywords:

Insecta; Microhabitat Association; Lotic Ecology; Naucoridae

Keywords Plus:

STREAM ECOLOGY; WATER-FLOW; HYDRODYNAMICS; BEHAVIOR;

DIPTERA; LARVAE

Abstract:

Samples (0.5 m2) were taken from the South Llano River,

Kimble County, Tex., to determine inter- and intraspecific

differences in microhabitat association for the three most

abundant species of Naucoridae. Various aspects of substratum

condition, current speed, temperature, depth, as well as complex

key hydraulic features, were used to characterize the

microhabitat for each sample. Eight species of naucorids occur

in the river; however, only Ambrysus circumcinctus Montandon,

Cryphocricos hungerfordi Usinger, and Limnocoris lutzi La Rivers

occurred with sufficient frequency in our samples to allow

statistical analysis. None of the three species exhibited age-

related differences in microhabitat association based on

multivariate analysis of variance (MANOVA), and none of the

examined abiotic variables yielded significant differences

between nymphs and adults when analyzed from a univariate

perspective except Froude number for L. lutzi. Both A.

circumcinctus and C. hungerfordi exhibited highly significant

differences (MANOVA) in abiotic characteristics between quadrats

of occurrence and nonoccurrence. Results of individual analyses

of variance (ANOVAs) indicated that 9 of the 10 abiotic

variables were significant for A. circumcinctus and 8 for C.

hungerfordi. In contrast, quadrats where L. lutzi occurred

could not be distinguished from those in which it was absent

based on MANOVA, and only two abiotic variables exhibited

significance in the ANOVAs. Associations between age groups

(nymphs and adults) within a species and between all possible

species pairs (combined age groups) also were evaluated with

contingency chi-2 tests using presence-absence data and with

Pearson's product-moment correlations using density data. In

all cases, significant negative associations were not detected,

suggesting that neither age groups nor species exhibit

microhabitat segregation. Discriminant function analysis for

each species supported MANOVA results on presence-absence data.

Separate multiple step-up regressions were used to evaluate

which abiotic factors were most related to the density for each

species. Significant variables included mean current speed,

which accounted for 23.8% of the variation in density of A.

circumcinctus; rock standard error of the mean, which accounted

for 43.1% of the variation in density of C. hungerfordi; Froude

number and depth range, which together accounted for 39.0% of

the variation in density of L. lutzi. In summary, each common

naucorid clearly shows microhabitat associations, but the

evidence of interspecific differences is indirect.

Клопы: водомерки Gerridae, экология.

Authors: Mclean-EB

Title: Sexual Dimorphism and Predaceous Feeding-Habits of the

Waterstrider Gerris-Remigis Say (Heteroptera, Gerridae)

Source: CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE

1990, Vol 68, Iss 12, pp 2688-2691

Language: English

Document type: Note

Addresses:

UNIV-TORONTO, ERINDALE COLL, DEPT ZOOL, INSECT BEHAV GRP,

MISSISSAUGA L5L-1C6, ONTARIO, CANADA

Keywords Plus:

WATER STRIDERS; TERRITORIALITY; SELECTION; SIZE

Abstract:

The feeding habits of Gerris remigis were examined in a

southeastern Ontario stream. Gerrids with prey items were

collected from two pools along a 15-m length of the site. The

size distribution of potential prey available in the surface

drift during the survey was estimated. Gerrid prey consisted

mainly of terrestrial insects; coleopterans, dipterans,

homopterans, and hymenopterans represented the predominant

orders. The median size of prey taken by all gerrids was

significantly larger than that available in the surface drift.

A sexual dimorphism in gerrid body size was found. The length

of prey taken did not differ between the sexes; however, the

diet of the larger bodied females consisted of prey with a

greater median body width than the diet of smaller males.

Females also took a greater size range of prey. These results

support a size-dependent predation model which predicts that the

upper size range of prey that can be successfully captured is

correlated with predator size.

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