Elevated CO2 Reared brown plant hopper as prey on feeding potential of wolf spider pardosa pseudoannulata

AbstractSpiders constitute an extensive and diverse branch of the phylum Arthropoda. Whereas the genomes of four web-weaver spider species and a single cave-living spider have been determined, similar studies have not been reported previously for a wandering spider. The pond wolf spider, Pardosa pseudoannulata, is a wandering hunter that immobilizes prey using venom rather than a web. It is also an important predator against a range of agriculturally important insect pests. The increasing interest in its wandering lifestyle and in the potential of spider venom as a tool for pest control have prompted a detailed study on this wandering spider species. We have generated a high-quality genome sequence of P. pseudoannulata and analysed genes associated with the production of silk and venom toxins. Sequencing reveals that P. pseudoannulata has a large genome of 4.26 Gb. The presence of only 16 spidroin genes and four types of silk glands is consistent with the moderate use of silk and the lack of a prey-catching web. A large number of genes encode neurotoxins and there is evidence that the majority are highly selective for invertebrates. Comparison between spider species reveals a correlation between spider neurotoxin selectivity for target organisms and spider prosoma size, suggesting a possible coevolution of these two features. The genome data provides valuable insights into the biology of P. pseudoannulata and its potential role as a natural enemy in pest control.

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Effects of elevated CO2 on resistant and susceptible rice cultivar and its primary host, brown plant hopper (BPH), Nilaparvata lugens (Stal)

10.21203/rs.3.rs-118055/v1 ◽

2020 ◽

Author(s):

Sengottayan Senthil-Nathan

Keyword(s):

Elevated Co2 ◽

Insect Pests ◽

Rice Cultivar ◽

Nilaparvata Lugens ◽

Carbon Accumulation ◽

Rice Cultivars ◽

Ambient Conditions ◽

Primary Host ◽

Nilaparvata Lugens Stål ◽

Brown Plant Hopper

Abstract Elevated CO2 has positive response on plant growth and negative response on insect pests. As a contemplation, the feeding pattern of the brown plant hopper, Nilaparvata lugens Stål on susceptible and resistant rice cultivars and their growth rates exposed to elevated CO2 conditions were analyzed. The elevated CO2 treatment showed significant differences in percentage of emergence and rice biomass that were consistent across the rice cultivars, when compared to the ambient conditions. Similarly, increase in carbon and nitrogen ratio of leaves and alterations in defensive peroxidase enzyme levels were observed, but was non-linear among the cultivars tested. Lower survivorship and nutritional indices of N. lugens were observed in conditions of elevated CO2 levels over ambient conditions. Results were nonlinear in manner. We conclude that the plant carbon accumulation increased due to elevated CO2, causing physiological changes that decreased nitrogen content. Similarly, elevated CO2 increased insect feeding, but did not alter other variables such as their biology or reproduction.

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