No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effects of alternating temperatures on Acarus siro L. (Acari: Acaridae)
Abstract
Fecundity, longevity and survival to adulthood ofAcarus siro (L.) at constant and alternating temperatures were compared. Both fecundity and longevity were affected by alternating temperatures but the effect of the frequency of alternations was not significant. Significantly higher fecundity and longer life spans were recorded at constant temperatures of 14 and 21°C than at 28°C or at alternating temperature regimes. Alternating temperature regimes in comparison to constant regimes did not significantly change the number of males and females surviving to adulthood or the sex ratio. However, the lowest number of adults surviving was recorded when temperatures were changed every 12 h and the highest at a constant temperature of 14°C.
... Mites, like beetles, are ectothermic, their metabolic activity and developmental rates increase with increasing temperature (Schowalter, 2006). Temperature is a key abiotic factor affecting the development of individuals and populations of mites, from those in stored products (Błoszyk & Robbert, 1985;Kawamoto, Sinha, Muir, & Woods, 1991) to those associated with bark beetles . The few studies that have looked at the effects of temperature on population growth of mites associated with bark beetles (Evans et al., 2011;Hofstetter et al., 2007;Lombardero et al., 2003) show a bump shaped pattern in growth rate in response to temperature, similar to that of fungi and bacteria shown earlier. ...
The ectosymbiotic community associated with bark and ambrosia beetles is diverse and speciose and adapted for life within tree tissues. This community—composed of fungi, bacteria, viruses, nematodes, and mites—interacts with beetle hosts in a variety of ways. Interactions are often not simple or clearly understood, and are rather context-dependent, shifting with changing environments. Ectosymbionts also interact with the tree and with natural enemies and competitors of beetle hosts within trees. In this chapter, we describe the effects of changing climate, especially elevated temperatures, on the composition and interactions of the ectosymbiotic community associated with bark and ambrosia beetles. We address (1) how changes in climate can differentially affect growth and reproduction of ectosymbiotic species, (2) how climate can drive changes in tree condition, increasing or decreasing secondary defenses, phloem nutrients, and moisture and affecting ectosymbionts associated with beetles, and (3) how climate change affects interactions among ectosymbionts, beetles, and trees.
... Finally, for the simulation of the granary observations, it might be important to take into consideration the effect of fluctuating temperature, although this should apply only to populations at the top layer of grain. Boczek and Davis (1985) showed that the fecundity of A. siro decreased to about half when exposed to such unstable conditions. A fluctuating temperature should also shorten the development. ...
The aim of the study was to develop a stage-structured within-patch model describing predator-prey interactions of Cheyletus eruditus (Schrank) and Acarus siro L. on stored grain. Parameterisation of the model was done using data from the literature. Due to considerable variance in these data, statistical methods were used to extrapolate the parameters. The results of the simulations were compared with the experimental control of A. siro by C. eruditus on wheat. The results indicated that all life-history studies of A. siro yielded overestimated parameters leading to an unnaturally rapid population growth of A. siro on grain. The main reason seems to be the use of high quality food (wheat germs), which considerably increased fecundity. A new model with reduced fecundity was found to correspond well with the observed dynamics in a granary. The model of C. eruditus, including parameters from different sources, produced dynamics quite similar to the observed one. A simulation of biological control under laboratory conditions, on 45g of wheat, showed that C. eruditus is able to control A. siro within the observed period. In contrast, simulation of the control in a granary showed a marked difference in comparison with the observed dynamics. The discrepancy is attributed to the effects of spatial factors, such as immigration. The predator-prey model developed here appears to be valid for the prediction of the local (within-patch) population dynamics of A. siro and C. eruditus on wheat grain at 20C and 80% RH.
Objective
To evaluate contamination of unopened and opened stored sources of commercial dry dog food by viable storage mites.DesignProspective laboratory and field study.Material and methodsSamples were collected from nine brands of previously unopened bags (new bags) of dry food and 20 field sources of stored dry food in homes in Sydney and Canberra, Australia. All samples were initially examined for the presence of mites using a stereo-binocular microscope and then placed in separate filter-paper-sealed containers. Field samples were incubated at an average temperature of 29°C and 78% relative humidity (RH) for 5 weeks and then at average 26°C/83% RH for 8 weeks. Paired new-bag samples were stored under room conditions (average 23°C/47% RH) and controlled incubator conditions (average 26°C/80% RH) for 6 weeks. All samples were thoroughly examined for mites, mite eggs and visible mould once weekly using a stereo-binocular microscope.ResultsStorage mites were not visualised in any of the field samples or in new-bag samples stored at room temperature. Storage mites, identified as Tyrophagus putrescentiae, were visualised in increasing numbers in seven of nine new-bag samples after incubation, with first mites and then eggs evident after 3 weeks of incubation.Conclusions
We confirmed the presence of viable storage mites in a range of previously unopened commercial dry dog foods in Australia and confirmed the possibility of heavy storage mite contamination for dry food stored under conditions of moderate temperature and high humidity. These findings have relevance to storage mite and/or dust mite sensitivity in canine atopic dermatitis.
This study aims to estimate the influence of three constant temperatures (20, 25 and 30°C) on the damage effect, population growth, life cycle and longevity of two stored-product mites (Tyrophagus putrescentiae and Aleuroglyphus ovatus) reared on the dried Shiitake mushroom (Lentinula edodes) at 80% relative humidity (r.h.) and 14:10 (L:D) h (light: dark) photoperiod. The weight loss of the Shiitake mushroom caused by T. putrescentiae and A. ovatus increased with increasing temperature. The increase in the count of T. putrescentiae and A. ovatus in the rearing cells led to noticeable decrease in the weight of the Shiitake mushroom. The results indicated that T. putrescentiae was more harmful than A. ovatus on the Shiitake mushroom. The r-values of both mite species increased with increase in temperature up to 25°C, whereas the value of r decreased when the temperature increased to 30°C. At 20, 25 and 30°C, the values of r were 0.167, 0.182 and 0.159 for T. putrescentiae and 0.126, 0.140 and 0.115 for A. ovatus, respectively. The developmental time of immature stages, reproductive periods and female longevity of T. putrescentiae and A. ovatus were adversely affected by the increase in temperature. The life cycle of T. putrescentiae varied from 9.26 to 20.64 days and that of A. ovatus ranged from 11.65 to 25.21 days when the temperature increased from 20 to 30°C. The longest longevity of T. putrescentiae and A. ovatus (38.37 and 48.18 days) was recorded at 20°C, whereas the shortest (20.38 and 28.40 days) was found at 30°C. The results showed that T. putrescentiae had lower developmental time and reproductive periods than A. ovatus when reared on the Shiitake mushroom at all the studied temperatures.
The flour miteAcarus siro L. (Acaridae, Astigmata) was reared on an axenic diet with the addition of various nutrient antagonists, with and without supplementation by the corresponding nutrients. The deficiency symptoms induced by dietary antagonists, and the reversibility of the former by nutrient administration, indicated that folic acid, riboflavin, thiamine, niacin, pyridoxine, biotin and a sterol are essential for the growth and reproduction of the flour mite. It was also demonstrated that the population density and generation sequence of this species can be suppressed to the level of acaristasis by nutrient antagonists, owing to inhibited nutrient utilization.
The pest potential of stored product mites depends on the reproduction rate that is affected by the environmental conditions. In this study we investigated the effect of temperature, ranging from 5 to 35°C, on the population growth of three important mite species, Acarus siro, Tyrophagus putrescentiae and Auleroglyphus ovatus at 85% r.h. Starting with 10 individuals the population increase of mites was observed after 3 weeks of cultivation, or after 6 weeks for those kept at low temperatures (5, 10, 12.5, and 15°C). The rate of increase was calculated for each temperature and species. The obtained data were fitted with polynomial models. The mite population growth rates increased with increasing moderate temperatures until 25°C, when r
m
-values were 0.179, 0.177 and 0.190 for A. siro, A. ovatus and T. putrescentiae, respectively. The lower development threshold was 10.2°C in all three species. Estimated upper temperature threshold was higher in T. putrescentiae (49°C) than in A. siro and A. ovatus (38°C). Simulation of the rate of population increase under ideal conditions, using real temperature records obtained from Czech grain stores, showed that the pest mite populations increase only during 3.5 months within a typical 9-month storage season in Central Europe. These results indicate that control of mites, be it chemical, physical or biological, is recommended during the months when allergens and pests are produced, i.e. from September to mid November and in May.
Development time of Tribolium castancum (Herbst) and Trogoderma iuclusum (LeConte) was reduced by about 9–12% when beetles were exposed to sinusoidal fluctuating temperatures with 10°C range and mean of 25°C rather than a constant 25°C. Sitophilus oryzae (L.) showed no significant difference in the effect of the 2 temperature conditions upon development time.
During the 1st 14 days after emergence, the fecundity of T. castancum was apparently greater in fluctuating than in constant temperature; fecundity of T. inclusum and S. oryzae was not different in the 2 temperature regimens.
A table of data gives percentage relative humidities over saturated solutions of eighty-eight different salts or salt mixtures. Remarks on the suitability of these solutions for humidity control are included.
A table is presented giving the minimum temperature and humidity at which 43 species of beetle, 9 species of moth and one mite can multiply sufficiently to become pests, and the range of temperature most favourable for each. An estimate of the maximum rate of increase for each species is also given.
Fluctuating temperatures are characteristic of the environment of most organisms, yet constant temperatures are most frequently used for laboratory studies on their life histories. The literature has been reviewed to point out some of the ways in which constant-temperature data for rates of development, developmental thresholds, fertility, and other life-history phenomena could be misleading when an ecologist attempts to model a natural system or to extrapolate to field conditions. To implement the replacement of constant-temperature studies with fluctuating temperature studies, 2 previously reported timer-controlled bimetallic or mercury thermostat devices and a new timer-controlled solid-state controller thresdevice are discussed. With the new device the maximum and minimum temperatures are set with 2 potentiometers, and a synchronous motor timer is used to switch between the 2 potentiometers. The earlier devices have the advantage of controlling the temperature throughout the cycle. However, with the new device the temperature drifts between maximum and minimum temperatures at a rate of 2–5°C per hour, and this rate is similar to the rate of change in the field. The new device has the advantage of a more easily changed temperature program and remote control of the temperature cabinet, with no need to place the entire device within the cabinet.
A rearing method for small insects and mites under controlled conditions
- J Boczek
- J. Boczek
Boczek, J., 1954. A rearing method for small insects and mites under controlled conditions. Ekol. Pol., 2:473--476 (in Polish).
A study on some aspects of ageing inAcarus siro L. (Acarina: Acaridae)
- J Boczek
- J Czajkowska
- J. Boczek
A study on some aspects of ageing in Acarus siro L
- J Boczek
- J Czajkowska
Boczek, J. and Czajkowska, J., 1973. A study on some aspects of ageing in Acarus siro
L. (Acarina: Acaridae). Ekol. Pol., 21: 173--184.