scholarly journals Intraspecific variations in life history traits of two pecky rice bug species from Japan: mapping emergence dates and number of annual generations

Author(s):  
Kazuhisa Yamasaki ◽  
Ken Tabuchi ◽  
Akihiko Takahashi ◽  
Takeshi Osawa ◽  
Akira Yoshioka ◽  
...  

The mirid bugs Stenotus rubrovittatus and Trigonotylus caelestialium, which cause pecky rice, have become a threat to rice cultivation in Asia. Damage caused by these pests has rapidly become frequent since around 2000 in Japan. Their expansion pattern is not simple, making it difficult to manage them by prediction. Some insects with wide distributions have locally adapted variations in life-history traits. We performed laboratory rearing experiments to assess the geographical scale of intraspecific variations in life-history traits of S. rubrovittatus and T. caelestialium. These were aimed at increasing the accuracy of occurrence estimates and the number of generations per year. These results were compared with previous research, and differences in development rates were observed between populations of different latitudes, but not of the same latitude. Finally, plotting the timing of adult emergence and the potential number of generations per year on maps with a 5-km grid revealed that they differed greatly locally at the same latitude. These maps can be used for developing more efficient methods of managing mirid bugs in integrated pest management.

2021 ◽  
Author(s):  
Kazuhisa Yamasaki ◽  
Ken Tabuchi ◽  
Akihiko Takahashi ◽  
Takeshi Osawa ◽  
Akira Yoshioka ◽  
...  

2019 ◽  
Vol 112 (6) ◽  
pp. 505-510 ◽  
Author(s):  
Brittny M Jones ◽  
Jeffery K Tomberlin

Abstract The black soldier fly, Hermetia illucens (L.), is economically important due to its use in waste management and as an alternative protein source for livestock, poultry, and aquaculture. While industry promotes mass production of the black soldier fly, little is known about the impact of larval competition on development time, resulting immature and adult weight, or adult longevity. The goal of this research was to examine the life-history traits of black soldier flies when reared at four densities (500, 1,000, 1,500, and 2,000 larvae/4-liter container) provided 54-g Gainesville diet at 70% moisture (feed rates of 0.027, 0.036, 0.054, and 0.108 g) every other day. Results were as expected with the lowest larval density (500) producing heavier individuals (by 26%) than the greatest larval density (2,000) across all life stages. In addition to weights, larvae reared at the lowest density developed 63% faster than those reared at the greatest density. In regard to pupal development time, those reared at the lowest larval density developed 3% slower than the greatest density. A 21% difference between the two extreme densities was found in survivorship to prepupal stage, with the lowest larval density having the greatest survivorship (92%) compared with the greatest larval density (70%). All densities displayed over 90% adult emergence rates. Such information is vital for optimization of the process of converting waste products to protein at an industrial scale with the black soldier fly.


2022 ◽  
Author(s):  
Pierre Marie Sovegnon ◽  
Marie Joelle Fanou ◽  
Romaric Akoton ◽  
Oswald Yédjinnavênan Djihinto ◽  
Hamirath Odée Lagnika ◽  
...  

The success achieved in reducing malaria transmission by vector control is threatened by insecticide resistance. To strengthen the current vector control programmes, the non-genetic factors underlying the emergence of insecticide resistance in Anopheles vectors and its widespread need to be explored. This study aimed to assess the effects of larval diet on some life-history traits and pyrethroid-insecticide susceptibility of Anopheles gambiae s.s. Three (3) An. gambiae strains, namely Kisumu (insecticide susceptible), AcerKis (homozygous ace-1 R G119S resistant) and KisKdr (homozygous kdr R L1014F resistant) were fed with three different diets (low, medium, and high) of TetraMin ® Baby fish food. Pre-imaginal developmental time, larval mortality, adult emergence rate and female wing length were measured. Mosquito females were exposed to insecticide-treated net (ITN) PermaNet 2.0 and PermaNet 3.0. In the three An. gambiae strains, significant differences in adult emergence rates ( F = 1054.2; df = 2; p <0.01), mosquito wing length ( F = 970.5; df = 2; p <0.01) and adult survival post insecticide exposure ( χ2 = 173; df = 2; p <0.01), were noticed among the three larval diets. Larvae fed with the low food diets took more time to develop, were smaller at emergence and displayed a short lifespan, while the specimens fed with a high regime developed faster and into big adults. Although being fed with a high diet, none of An. gambiae strain harbouring the kdr R and ace-1 R allele survived 24 hours after exposure against PermaNet 3.0. This study showed that variation in the larval diet significantly impacts An. gambiae life-history traits such as larval mortality and developmental time, adult wing length, and female susceptibility to pyrethroid insecticides. Further investigations through field-based studies would allow an in-depth understanding of the implications of these non-genetic parameters on the physiological traits of malaria vectors and consequently improve resistance management.


2017 ◽  
Vol 69 (2) ◽  
pp. 335-344 ◽  
Author(s):  
Aylin Er ◽  
Deniz Taşkıran ◽  
Olga Sak

The effects of the botanical insecticide azadirachtin were examined on the life history traits, fecundity and immune parameters of Galleria mellonella L. (Lepidoptera: Pyralidae). We determined that for the topical application of azadirachtin, the LC50 was 16.564 ppm; at 100 ppm the adult emergence time was prolonged, however the longevity of adults remained unchanged above sublethal concentrations. The mean number of healthy eggs and the fecundity of adults decreased, whereas the number of defective eggs increased with azadirachtin treatment. At concentrations >50 ppm female G. mellonella adults laid no eggs. Azadirachtin reduced total hemocyte counts at 24 and 48 h posttreatment, however the alterations in differential hemocyte counts were only significant at 100 ppm. Laminarin-induced nodulation response and the spreading ability of hemocytes were also suppressed with azadirachtin treatment. Our results suggest that azadirachtin, as a good candidate for integrated pest control, has the capability to affect the biological parameters and cellular immunity of the model insect G. mellonella.


Author(s):  
Olivia Rincón-Betancurt ◽  
Marysol Aceituno-Medina ◽  
Luz Verónica García-Fajardo ◽  
Emilio Hernández

Abstract For purposes of mass-rearing fruit flies, nutrient intake through artificial diets is a challenge, artificial food content and processing should promote sufficient absorption and availability to ensure fly fitness. Bulking agents play an essential role in creating a quality diet, but its physical characteristics, such as particle size, may establish a better microenvironment for feeding and development. Currently, there is a lack of information about protein metabolism in mass-reared fruit flies. Therefore, we evaluated whether the particle size of the bulking agent affects the absorption and excretion of the proteins, as well as their effect on the life-history traits of Anastrepha obliqua. We determined the protein content of hemolymph and feces, as well as the presence of nitrogen end-products as indicators of their level of absorption in a diet elaborated with coarse and fine corn cob particles as a bulking agent. The bromatological composition showed that coarse particles increased the bioavailability and content of crude, digestible, and soluble protein for the diet and hemolymph protein of larvae alike. We found an inverse relationship between the protein content of the hemolymph and feces of the larvae. Ammonium was determined to be a product of the catabolism of proteins. Also, A. obliqua improved its development (yield and pupal weight) and fitness (adult emergence and flight ability) when larvae were reared on a coarse particle diet. In conclusion, a diet elaborated with a coarse bulking agent features increased protein bioavailability and nutritional quality, which, in turn, increases the life-history traits of A. obliqua.


2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.


2020 ◽  
Vol 27 (4) ◽  
pp. 195-200
Author(s):  
Ufuk Bülbül ◽  
Halime Koç ◽  
Yasemin Odabaş ◽  
Ali İhsan Eroğlu ◽  
Muammer Kurnaz ◽  
...  

Age structure of the eastern spadefoot toad, Pelobates syriacus from the Kızılırmak Delta (Turkey) were assessed using phalangeal skeletochronology. Snout-vent length (SVL) ranged from 42.05 to 86.63 mm in males and 34.03 to 53.27 mm in females. Age of adults ranged from 2 to 8 years in males and 3 to 5 years in females. For both sexes, SVL was significantly correlated with age. Males and females of the toads reached maturity at 2 years of age.


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