Use of micro-CAT scans to understand cowpea seed resistance to Callosobruchus maculatus

Abstract Background The thermal plasticity of life-history traits receives wide attention in the recent biological literature. Of all the temperature-dependent traits studied, developmental rates of ectotherms are especially often addressed, and yet surprisingly little is known about embryonic responses to temperature, including changes in the thermal thresholds and thermal sensitivity during early development. Even postembryonic development of many cryptically living species is understood superficially at best. Results This study is the first to estimate the exact durations of developmental stages in the cowpea seed beetle C. maculatus from oviposition to adult emergence at five permissive constant temperatures from 20 to 32 °C. Early embryonic development was tracked and documented by means of destructive sampling and subsequent confocal imaging of fluorescently stained specimens. Late embryonic and early larval development was studied with the use of destructive sampling and light microscopy. Well-resolved temporal series based on thousands of embryos allowed precise timing of the following developmental events: formation of the blastoderm; formation, elongation, and retraction of the germ band; dorsal closure; the onset and completion of sclerotization of the cuticle; hatching, and penetration of the first-instar larva into the cowpea seed. Pupation and adult eclosion were observed directly through an incision in the seed coat. The thermal phenotype of C. maculatus was found to vary in the course of ontogeny and different stages scaled disproportionately with temperature, but pitfalls and caveats associated with analyses of relative durations of individual stages are also briefly discussed. Conclusion Disproportionate changes in developmental durations with temperature may have important implications when study design requires a high degree of synchronization among experimental embryos or when the occurrence of particular stages in the field is of interest, as well as in any other cases when development times need to be estimated with precision. This work provides one of the first examples of integration of embryological techniques with ecophysiological concepts and will hopefully motivate similar projects in the future. While experiments with Drosophila continue to be the main source of information on animal development, knowledge on other model species is instrumental to building a broader picture of developmental phenomena.

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Effect of Cowpea Seed Beetle (Callosobruchus maculatus) Infestation on Selected Landraces of Bambara Groundnut During Storage

Bioremediation Science and Technology Research ◽

10.54987/bstr.v9i2.624 ◽

2021 ◽

Vol 9 (2) ◽

pp. 31-34

Author(s):

Isma’ila Muhammad ◽

Nasiru Abdullahi ◽

Abdulmalik Bala Shu’aibu ◽

Ibrahim Musa ◽

Bawa Zakari Gambo ◽

...

Keyword(s):

Storage Time ◽

Callosobruchus Maculatus ◽

Bambara Groundnut ◽

State University ◽

Sources Of Resistance ◽

Improvement Program ◽

Randomized Design ◽

Percentage Weight ◽

Cowpea Seed ◽

Completely Randomized Design

The study was carried out to assess the effect of Callosobruchus maculatus infestation on selected Bambara groundnut (Vigna subterranean) landraces in Gombe during storage to determine the Landrace (s) that are less susceptible to infestation caused by C. maculatus during storage. The trial was done in the Botany laboratory of Gombe State University, Gombe. Seeds were collected from five different Landraces, 40 grams each of healthy and C. maculatus infestation free seeds were infested with two males and three females. Completely Randomized Design (CRD) with three replicates was used to assess the effects of C. maculatus infestation on the selected landraces of Bambara groundnut during storage. The results of the analysis of variance displayed significant differences (p≤ 0.05) among the parameters studied. It indicated that the Mottled and Cream landraces are relatively less susceptible and witness lower damage from the bruchids attack 14.6 (36%) and 17 (46%), whereas Red and Black landraces are more susceptible 24 (61 %) and 22 (57 %) (recorded higher damage from the C. maculatus in terms of percentage weight loss recorded). These results showed the existence of variation among the different Bambara groundnut landraces used due to the infestation of C. maculatus. It can be observed from this study that the use of infestation free landraces at storage time may perhaps be a worthwhile and auspicious factor for integrated pest management especially on bruchids in Bambara groundnuts. additionally, Mottle and Cream landraces might be employed as sources of resistance genes for the subsequent plant improvement program.

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Effects of interaction between cowpea variety and the application of plant powders on Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae) infestation of stored cowpea seeds

Annals of Tropical Research ◽

10.32945/atr4213.2020 ◽

2020 ◽

pp. 33-44

Author(s):

Owolabi Moshood Azeez ◽

Adebola Adedoyin Osipitan ◽

Isaac Oludayo Daniel ◽

Olufemi Olutoyin Richard Pitan

Keyword(s):

Callosobruchus Maculatus ◽

Adult Emergence ◽

Adult Mortality ◽

Management Scheme ◽

Cowpea Seeds ◽

Randomized Design ◽

Hyptis Suaveolens ◽

Plant Powders ◽

Seed Resistance ◽

Cowpea Variety

An integrated pest management scheme involving seed resistance and the application of powder of Cymbopogon citratus, Alstonia boonei, Hyptis suaveolens, Azadirachta indica, Loranthus braunii and Lycopersicum esculentum as protectant against the seed bettle, Callosobruchus maculatus (Fabricius), was evaluated in the laboratory at ambient temperature (29±3°C) and relative humidity (65±5%). Six resistant cowpea accessions selected from previous studies were treated with the six plant powders at 1.25% w/w in a 6×7 factorial arrangement fitted into a completely randomized design with five replicates. Seed treatment with any of the six plant powders on six accessions resulted in significantly higher adult mortality, lower oviposition rate, adult emergence inhibition, lower seed damage and higher seed germination over the control, Protection ability of the plant powders was influenced by the cowpea accessions used.

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