First report on field biology of the blister beetle, Meloe proscarabaeus L. (Coleoptera: Meloidae) in the Western Desert Agro-Ecosystem, Egypt

Blister beetles are phytophagous insects observed attacking various crops, including faba beans, peas, clover, wheat, and onions. These beetles feed on plant foliage and flowers, causing significant defoliation and crop losses. Additionally, they secrete cantharidin, a potent toxin harmful to livestock and domestic animals that consume contaminated plants. The field biology of M. proscarabaeus was studied during two successive seasons in faba bean fields. The obtained results showed that the pest develops to one generation per year. Beetles emerge from the 1st of December to the 4th of March with peak adults in late January. Females oviposit between early January and mid-April, laying an average of 2,475.8 eggs in the soil. The eggs' incubation period averaged 23.3 days, with a hatchability rate of 92.05%. The larvae undergo hypermetamorphic development, passing through three distinct phases. The active 1st & 2nd instar larvae, known as triungulins, feed on grasshopper, leafhopper, and honeybee eggs, with each instar lasting an average of 4.0 and 4.5 days, respectively. The inactive fifth and sixth instar larvae survive in soil chambers for 13.6 and 17.0 days on average. The Seventh instar larvae undergo aestivation in the soil for approximately 95.3 days under adverse environmental conditions. The duration of the pupal stage ranges on average from 43.3 days. Study illustrated mating and oviposition behaviors and emphasized the need for effective pest control measures based on field biology and monitoring techniques.