The effect of humidity on the development and survival of the immature stages of strains of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) at constant temperatures

doi:10.1016/0022-474X(90)90017-M

Journal of Stored Products Research

Volume 26, Issue 3, July 1990, Pages 163-167

https://doi.org/10.1016/0022-474X(90)90017-M Get rights and content

Abstract

The influence of humidity on the development and survival of a large, an intermediate and a small strain of Oryzaephilus surinamensis (L.) on kibbled wheat was studied. Three humidities, 30, 50 and 70% r.h., were used, over the temperature range of 17.5–35°C. At 17.5°C, eggs of the large and intermediate strains hatched at each humidity whereas the eggs of the small strain failed to hatch at humidities below 70% r.h. Larvae of all three strains died at 17.5°C, 30% r.h. At 17.5°C, 50 and 70% r.h., as well as at 20 and 35°C at 30% r.h., larval survival was higher for the large than for the two smaller strains. At 17.5°C, 50 and 70% r.h., pupae of all strains died as did those of the intermediate and small strains at 20°C, 30% r.h. Pupal survival was relatively high for the large strain over the range 22.5–35°C at 30% r.h. The pupal survival of each strain decreased with decreasing humidity even at temperatures favourable for development.

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Cited by (12)

Feeding substrate and temperature interplay determining infestations and losses by the sawtoothed grain beetle (Oryzaephilus surinamensis)
2021, Journal of Stored Products Research
Citation Excerpt :
In addition, the larva is also the most feeding active stage (Breese, 1961; LeCato and McCray, 1973; Beckett and Evans, 1994; Nika et al., 2020). Interestingly, this stage has the potential to live under unfavorable conditions and thus influence the traits of the following insect stages (Jacob and Fleming, 1990; Throne et al., 2003; Govindaraj et al., 2014). One of the most interesting findings of the current study was the fact that the increase in temperature directly affected the insect's response to living substrates, especially in dry dates with a relatively higher moisture content compared to rice and sesame.
Sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), is a secondary pest of stored products and one of the serious insect pests of cereal grains, commodities and packaged food throughout the world. However, this species is a concern beyond cereal grains, what may be differentially affected by temperature. Therefore, insect developmental time, larva and pupa survival, and adult emergence of O. surinamensis were assessed on different substrates (rice, sesame and date palm) at different temperatures (20, 25, 30 and 35 °C and 65% r.h). The substrate loss incurred by this insect infestation was also recorded. The larval stage was the main determinant for the overall developmental time of the sawtoothed grain beetle, regardless of the substrate and temperature tested. Adult emergence was affected by substrate (F_2,48 = 4.50, P = 0.02) and particularly temperature (F_3,48 = 24.94, P < 0.001), but not their interaction (F_6,48 = 0.40, P = 0.87), exhibiting little variation until reaching 30 °C, but with a quick decline at 35 °C. The performance of the insects in rice was better, and worse in dry date. Furthermore, the survival was inversely related to substrate loss, regardless of the substrate used for rearing the sawtoothed grain beetle. Thus, substrate and temperature range are major determinants of sawtoothed grain beetle infestation with consequences for this species management.
Feeding and egg-laying preferences of the sawtoothed grain beetle Oryzaephilus surinamensis: Beyond cereals and cereal products
2021, Journal of Stored Products Research
Citation Excerpt :
On the other hand, the interaction between different grains and moisture can affect the insect's biological properties. Jacob and Fleming (1990) showed that two out of three strains could not survive on kibbled wheat at 20 °C and 30% RH, while only 4% of the initially exposed larvae of the third strain became adults. Furthermore, the food dryness influenced movement and survival of O. surinamensis larvae and adults (Latifian et al., 2020).
The insect's response to various living substrates is an important determinant for their life history and demography reflected in their feeding and egg-laying preferences. However, research on polyphagous stored product insects such as the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), are largely focused on cereal grains neglecting its alternative hosts. Therefore, this study examines the effect of a range of 16 host substrates including dry fruits, nuts, oil and legume seeds on insect development, survival, and adult emergence of the sawtoothed grain beetle, besides of also determining the feeding substrate weight loss. Overall, the feeding substrates exhibited a significant and different effect on O. surinamensis, except egg incubation time and length of the pupal period. The longest larval periods were observed on legumes followed by oilseeds and (dry) fruits. The highest survival and adult emergence were recorded on fruits and nuts, except raisin, but significantly lower than when fed on legume seeds, including soybean. The losses in fruits and nuts were higher, particularly on almonds and cashew. Larva development was inversely correlated to survival and adult emergence, which were positively correlated to substrate loss. Our study indicated that several non-grain commodities such as (dry) fruits and nuts are rather suitable substrates for the population growth of O. surinamensis, an additional concern for in international trade.
Developmental and reproductive biology of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on seven commodities
2020, Journal of Stored Products Research
Citation Excerpt :
However, Govindaraj et al. (2014) found that O. surinamensis is able to complete its development from egg-to-adult on wheat and rice intact kernels within 39.1 and 37.5 days respectively. On the other hand, Jacob and Fleming (1990) showed that two out of three strains couldn’t survive on kibbled wheat at 20 °C/30% RH while only 4% of the initially exposed larvae of the third strain became adults. All these differences could be partially explained by the type and/or level of milled kernels that crucially affect the developmental performance of insects.
This study examines the effect of semolina, cracked wheat, maize flour, cracked maize, whole oat flakes, whole barley flour and cracked barley on the developmental and reproductive biology of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). The pest completed its development at all tested commodities except semolina and cracked wheat, while females did not produce eggs on maize flour and cracked barley. The developmental time of larvae was significantly longer when O. surinamensis fed on whole oat flakes (20.3 days) and whole barley flour (19.2 days) compared with maize flour (16.6 days) or cracked maize (17.2 days). The developmental duration of larvae fed on cracked barley (18.3 days) did not differ significantly when fed on cracked maize or whole barley flour, but it was significantly longer compared to maize flour and significantly shorter compared to whole oat flakes. The tested commodities did not affect the pupal development, which ranged between 4.6 and 4.7 days. The highest fecundity was recorded when O. surinamensis fed on cracked maize (4.8 eggs/female) and whole oat flakes (0.3 eggs/female). The tested commodities also affected the risk of death of O. surinamensis and its mean survival time. The shortest survival time was recorded on cracked wheat (11.1 days) while the longest was on cracked maize and whole oat flakes (37.8 and 42.2 days, respectively). The calculation of demographic parameters was feasible only on cracked maize. The net reproductive rate, the intrinsic rate of increase, the finite rate of increase and the mean generation time were 1.48 females/female, 0.01 females/female/day, 1.01 and 37.1 days, respectively. These results may be useful for improving the knowledge on the biology of this species and its potential spread.
Effect of temperature and humidity on the biology of Attagenus fasciatus (Thunberg) (Coleoptera: Dermestidae)
2011, Journal of Stored Products Research
Citation Excerpt :
Humidity had no effect on the pupal survival at 30 °C but some effect was evident at 35 °C. In Oryzaephilus surinamensis (L.), the pupal survival of each strain decreased with decreasing humidity even at a temperature favorable for development (Jacob and Fleming, 1990). The present data show that temperature and humidity strongly affect female fecundity and fertility as there was a negative correlation between temperature and fecundity, while the correlation was positive with humidity, indicating that lower temperature (30 °C) and higher humidity (80%) were more favorable than the higher temperature (35 °C) and the lower humidity (40% and 60% r.h) for this species.
The effect of temperature and relative humidity (r.h.) on the biology of the carpet beetle Attagenus fasciatus was studied under laboratory conditions. The influence of two temperatures (30 °C and 35 °C) and three humidities (40, 60 and 80% r.h.) on the number, duration, mortality and pupation of larval instars, as well as on the biology of fed and starved adult beetles, was investigated. Attagenus fasciatus larvae were reared on dried milk. The mean duration of each successive larval instar generally increased slightly but there was much fluctuation, particularly for the later instars. The highest mortality was recorded during the first two or three instars. At 30 °C pupal duration decreased with increasing r.h. while at 35 °C there was a slight increase. However, the duration at 35 °C was always shorter than at 30 °C. There was 100% emergence of adults from pupae under all test conditions except 40 and 60% r.h. at 35 °C where it fell to about 90%. Humidity and starvation strongly affected egg hatchability under all conditions tested. At 35 °C, eggs took less time to hatch than at 30 °C and there was a positive correlation between egg duration and r.h. The duration of the egg stage was longer for eggs of starved females than those of fed ones. Adult longevity was longer at higher humidity, females lived longer than males and unmated beetles lived longer than mated ones. Starvation reduced adult longevity in all cases. The sex ratio was male biased at 30 °C except at 80% r.h. but the reverse was true at 35 °C.
The effects of temperature and humidity on oviposition and developmental period of Oryzaephilus mercator (Fauvel)
1996, Postharvest Biology and Technology
In a laboratory assessment of the potential tolerance of the Merchant beetle, Oryzaephilus mercator (Fauvel), to temperature and humidity, both adults and immature stages were exposed to different levels of these factors.
Temperatures investigated were 20, 30 and 37 °C and relative humidities (RHs) were 30, 50, 70 and 90%. There were significant direct and interactive effects of the factors on oviposition so that higher numbers of eggs were laid as both temperature and RH increased. Low temperature and low humidity, however, inhibited the hatching of these eggs, and no larvae were produced at 20 °C and 30% RH, even with prolonged incubation. Temperature appeared to be a more important factor determining the duration of the life-cycle of this beetle as its development was generally quicker with increasing levels of this factor. Oilseeds may be less susceptible to O. mercator in agroecologies with sub-tropical climates where temperatures and humidities are relatively low.
The demography of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on kibbled wheat
1994, Journal of Stored Products Research
Finite rates of population increase (λ) of a pesticide susceptible strain of Oryzaephilus surinamensis (L.) living in kibbled wheat were determined at 20, 22.5, 25, 30, 32.5 and 35°C at 30, 50 and 70% relative humidity (r.h.) using survivorship and fertility schedules, i.e. observed numbers of adult offspring produced by cohorts of insects over a physiological time frame of twice the immature development period at each condition.
Population growth rate increased with temperature up to 30°C at 30% r.h. and up to 32.5% at 50 and 70% r.h. Populations subjected to drier conditions grew slower than those subjected to moister conditions. The greatest value of λ (2.4122) was observed at $32.5° C 70% r.h.$ The rate of population increase declined rapidly after a maximum value was reached and at $35° C 30% r.h.$ a negative rate of increase was observed. The value of λ at low temperatures was little affected by relative humidity with a minimum theoretical population growth threshold varying from 19.0 to 19.4°C between 30 and 70% r.h.
Egg to adult development and immature age-specific mortality were examined in detail at 20, 30 and 35°C at 30, 50 and 70% r.h. Minimum mortality occurred at 30 and 35°C at 70% r.h. and maximum mortality occurred at 20 and 35°C at 30% r.h. Maximum mortality accounted for almost complete extinction of the immature population and occurred mainly during the egg stage. At increasingly suboptimum conditions, a larger proportion of surviving immatures required an extra instar before pupation.
Demographic data for O. surinamensis were compared with other available data for the species, as well as with similar data for Sitophilus oryzae and Rhyzopertha dominica. Concerns were raised about relating estimates of population growth of O. surinamensis to wet bulb temperature. It was considered that relating population growth to dry bulb temperature and relative humidity or equilibrium grain moisture content, in the conventional manner, was more appropriate for this insect.

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Journal of Stored Products Research

Abstract

References (9)

A strain of small Oryzaephilus surinamensis (L.) (Coleoptera, Silvanidae) from the Far East

J. stored Prod. Res.

A horned strain of Oryzaephilus surinamensis (L.) (Coleoptera, Silvanidae) from the Mediterranean region

J. stored Prod. Res.

A summary of estimates of optimal and minimal conditions for population increase of some stored products insects

J. stored Prod. Res.

A parameter for expressing the suitability of an environment for insect development

J. stored Prod. Res.

Cited by (12)

Feeding substrate and temperature interplay determining infestations and losses by the sawtoothed grain beetle (Oryzaephilus surinamensis)

Feeding and egg-laying preferences of the sawtoothed grain beetle Oryzaephilus surinamensis: Beyond cereals and cereal products

Developmental and reproductive biology of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on seven commodities

Effect of temperature and humidity on the biology of Attagenus fasciatus (Thunberg) (Coleoptera: Dermestidae)

The effects of temperature and humidity on oviposition and developmental period of Oryzaephilus mercator (Fauvel)

The demography of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) on kibbled wheat