ISSN:0022-104X    

DOI:10.1002/jez.1402220302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractStudies on the water relationships of arthropods originated from the needs of applied entomology early in this century. Saturation deficiency (S.D.) was hailed as a measure whereby the effects of temperature and humidity on transpiration, and thus on development and longevity, could be simply combined. Errors in curve fitting and lack of physiological knowledge led to early misconceptions, but S.D. helped to focus attention on the need for laboratory analysis of field data and played a part in the move toward a more scientific approach leading to a great expansion of the whole field. Application of the concept to arthropods has usually been controversial, and examples of this drawn from the literature on the bionomics of the plague fleas and on cuticular waterproofing are discussed. A controversy exists at present concerning S.D. and the physics of transpiration. The concept of S.D. has been most useful where it has stimulated research to find out how arthopods avoid its consequences.

ISSN:0022-104X    

DOI:10.1002/jez.1402220303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractOosorption in response to desiccation stress was tested in spirostreptid millipedes from arid environments. Seasonally collected and experimentally stressed adult females were examined for penetration of oocytes by trypan blue, for compartment levels of water in cuticle + tissue and gut + gut contents, and for hemolymph osmolalities.Archispirostreptus syriacusfrom the winter‐rainfall Judaean and Negev deserts decreased in total body water during the hot dry summer. Simultaneously, water in cuticle + tissue and in gut + gut contents increased and decreased respectively in proportion to total water. Water in both compartments decreased in starved specimens exposed for 19 days to 76% relative humidity; these millipedes resorbed a higher percentage of oocytes than did field controls but not more than specimens in saturated air.Groups of starved premolt (spring) and postmolt (summer)Orthoporus ornatusfrom New Mexico (summer rainfall) each responded differently when exposed to humidities found in their respective habitats. Compartment water levels in the former remained constant for 19 days under moderate conditions; they declined in the latter after 36–42 days of relative moisture stress. Neither stage showed increased oosorption over field controls when exposed to seasonal humidity ranges.Archispirostreptus syriacusresorbed a higher proportion of oocytes than didO. ornatus, which matured oocytes only in summer rather than most of the year. Patterns of oosorption and oocyte development probably reflect species‐specific life histories and relative states of starvation rather than seasonal water balance and desiccation s

ISSN:0022-104X    

DOI:10.1002/jez.1402220304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractLava tube caves in the Hawaiian Islands contain an impressive array of troglobitic arthropod species. These animals exhibit striking morphological adaptations to their subterranean environment including loss of eyes and body pigment, reduction or elimination of wings, and hypertrophication of chemosensory and tactile organs. Certain modifications of water balance and metabolic rates are also apparent in these cave‐adapted animals.Neither Hawaiian troglobites nor their surface relatives can absorb water vapor from a saturated atmosphere even following a period of prolonged desiccation, whereas both forms are able to restore water deficits adequately through drinking. Lava tube crickets (34.5 and 52.3 μg cm−2hour−1mmHg−1) and spiders (33.4 μg cm−2hour−1mmHg−1) possess greater integumentary permeabilities than their epigean relatives (crickets, 26.2; spiders, 3.1 μg cm−2hour−1mmHg−1).Hawaiian troglobitic crickets lack a diel metabolic rate (night = 279.5 ± 20.1; day = 280.8 ± 13.5 μl 02gm−1hour−1). The daily average metabolic rates of cave‐adapted (280.2 ± 15.3) and surface crickets (277.4 ± 9.8 μl 02gm−1hour−1) are not significantly different (P>0.05), however, suggesting differential strategies of caloric utilization in the two environments whic

ISSN:0022-104X    

DOI:10.1002/jez.1402220305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractLipids (waxes) deposited on or incorporated in the epicuticle provide an important waterproofing barrier in most terrestrial insects and arachnids. Although the chemical nature of these lipids is well documented, ultra‐structural evidence for their association with specific cuticular layers and sublayers is less conclusive. Difficulties here include relating layers observed with the electron microscope with layers seen under light microscopy, plus the fact that much lipid is removed in normal preparative procedures for electron microscopy. Moreover, epicuticular layers which presumably are lipid‐rich are often resistant to organic solvents. The latter suggests that if lipid is present, much of it is bound, possibly to protein. Preliminary studies using new techniques such as myrcene partitioning and freeze‐fracture microscopy which improve lipid rétention and visualization have yielded some promising results. Scanning electron microscopy of surface waxes, in contrast, has revealed complex lipid accumulations which can be altered or removed by appropriate organic solvents. Surface waxes no doubt supplement lipids associated with epicuticular layers in restricting water loss, with the effectiveness of the former being dependent upon their thickness, physical structure and arrangement, and their chemical composition. Pore and wax canals are likely the major routes via which lipids are transported from sites of synthesis to the epicuticle, but the exact mechanisms involved must still be re

ISSN:0022-104X    

DOI:10.1002/jez.1402220306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe effects of larval and pupal thermal regime on adult transcuticular water loss rates and epicuticular hydrocarbon composition inDrosophila pseudoobscurawere determined. Temperatures encountered by the larval stage had no effect, but flies emerging from pupae maintained at 24°C exhibited significantly lower cuticular permeabilities than those emerging from pupae maintained at 17°C. More than 50% of the variance in cuticular permeability was accounted for by variation in the proportion of n‐pentacosadiene in the epicuticular hydrocarbons. High transcuticular water loss rates were correlated with higher proportions of relatively short‐chain, methyl‐branched alkanes and alkadienes. High proportions of longer chain lengths of both branched alkanes and alkadienes were associated with lower cuticular permeabilities. The molecular basis for these findings is di

ISSN:0022-104X    

DOI:10.1002/jez.1402220307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractA new, flow‐through system for the concurrent measurement of water loss and CO2production from arthropods is described. The system employs an Al2O3sensor to measure the moisture content of the air stream, and an infrared gas analyzer to determine the CO2content. The system responds rapidly, is accurate, and provides a continuous record of both variables at constant or increasing temperatures. Preliminary studies on the house cricket,Acheta domesticus, showed that water loss and V̇ CO 2were highly variable depending upon the activity of crickets and that water loss increased greatly as a result of oral and anal discharges of fluid. Occlusion of the mouth and anus (paraffin) reduced water loss and V̇ CO 2at 30°C by 82 and 46%, respectively. Strong correlations between V̇ CO 2and water loss were observed in crickets whose mouth and anus had been sealed, both in long‐term (3 hour) isothermal studies and under conditions of rapidly inc

ISSN:0022-104X    

DOI:10.1002/jez.1402220308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractStudies of water loss during metamorphosis of insects have usually been confined to the pupal stage where both cuticular and respiratory control of transpiration have been reported. InManduca sextaand other lepidopterans, preparation for pupation actually begins several days before pupation when the animals stop feeding and begin searching for an appropriate pupation site, a burrow forM. sexta. This study examines some aspects of water balance maintenance from the initial period of searching to the final time of eclosion. Behavior is important for reducing water loss, as animals which fail to find an appropriate pupation site continue to lose water at twice the rate of animals which are burrowed (10 vs. 5 mg H2O/g·h). Part of this is explained by exposure to light as unburrowed animals in constant dark are intermediate in water loss. The epicuticle during the pupal stage reduces water loss rate eight to tenfold, removal causing animals to lose water at 4 mg (g·h)−1.M. sextadoes appear to be capable of storing water in preparation for metamorphosis, since individually raised animals consistently have water contents higher than animals reared in large groups. A drop in water loss during the larva‐pupal development is correlated with increased hemolymph ecdysone titer, although how is unknown. Pupal water loss can be divided into cuticular and respiratory pathways, with cuticular loss accounting for two‐thirds of 0.7 mg H2O (g·h)−1loss rate. Finally, an increase in hemolymph osmotic pressure just prior to ecdysis may aid in reclamation of mol

ISSN:0022-104X    

DOI:10.1002/jez.1402220309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractSeveral patterns of uric acid voiding exist among various cockroach species. The impact of dietary nitrogen levels on these patterns has now been examined.Blattella germanica, Supella longipalpa, andLatiblattella inornatado not void uric acid even when maintained on diets containing 10.6% nitrogen for up to 30 days. Two species ofNahublattellavoid some uric acid on that diet, but high mortality was observed by 15 days.Parcoblatta fulvescensvoids increasing amounts of uric acid as formed pellets when dietary nitrogen is increased, and suffers no untoward effects. The partitioning of injected14C‐purine (hypoxanthine) byParcoblattawas shown to occur first by conversion to14C‐uric acid. Thereafter,14C is found in evolved14CO2, feces, egg cases, and whole body. The partitioning of14C is influenced by the level of dietary nitrogen available. On a nitrogen‐restricted diet, larger amounts of14CO2are evolved but little14C occurs in the feces. When nitrogen is abundant, reduced amounts of14CO2are evolved and more14C is voided with the feces.14C‐containing compounds, including14C‐uric acid, are incorporated into egg cases. Radiolabel remaining in the injected insects at the end of the experiment was also influenced by the dietary regime. These results are discussed in relation to the flow of uric acid throughParcoblattaand its utilization by th

ISSN:0022-104X    

DOI:10.1002/jez.1402220310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe carpenter beeXylocopa capitatahas a high wing loading (425 mg cm−2in females with empty crops) and exhibits a very high mass‐specific oxygen consumption during flight (mean for free flight 52.3 ml O2gm−1hour−1). Evaporative water loss is also high during flight (26.6 mg gm−1hour−1) and is significantly correlated with rate of oxygen consumption (r = 0.73) as well as with temperature of the ambient air (r = 0.80) and the water vapor deficit (r = 0.66). No indication of active evaporative cooling was evident and the bees are true endotherms capable of rapid preflight thermogenesis. Analysis of the osmotic and ionic concentrations of the body fluids showed that no water stress was experienced by the bees.The use of suitable thermocouples and a sensitive capacitance‐type humidity meter in an open flow‐through system allowed instantaneous and simultaneous measurement of oxygen consumption, evaporative water loss, and thoracic temperature. All three variables fluctuated in close synchrony during preflight warmup, flight, and sub

ISSN:0022-104X    

DOI:10.1002/jez.1402220311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY