温度和光周期影响两种同域发生瓢虫同种和异种组合时的猎物消耗量和利用率

Temperature and photoperiod influence prey consumption and utilization by two sympatric Coccinella species( Coleoptera: Coccinellidae) in conspecific and heterospecific combinations

【目的】印度次大陆是世界上最脆弱的地理景观。气候条件的略微变动可能对其季节周期可能产生不良影响,并引起农业生态系统中蚜虫的大暴发。七星瓢虫Coccinella septempunctata L.和狭臀瓢虫C.transversalis Fab.是该次大陆上广泛分布、同域发生的两种食蚜性瓢虫。【方法】设计异地试验,来探究同种和/或异种组合时的这两种瓢虫用共同的猎物资源(豌豆蚜)饲养时,对增加的温度(15,20,25,30和35℃)和光周期(8L∶16D,12L∶12D和16L∶8D)的响应。【结果】结果表明,在这5个不同温度和3个不同光周期条件下,同种或异种组合时这两种瓢虫表现出了拮抗作用。尽管表现出拮抗作用,但是同种或异种组合的两捕食动物在25℃和长光周期(16L∶8D)条件下消耗、转化和利用的猎物生物量最大。然而,它们的猎物消耗率、转化效率和生长速率在异种组合中最高。在5个不同温度下,4龄幼虫均更有效地利用猎物生物量,将其转变成自身生物量,而雌成虫在3个不同光周期条件下也是如此。【结论】因此可以推断,增加的温度和光周期条件可能不会阻止同种和异种组合中的瓢虫发生拮抗作用,但是在25℃和长光周期(16L∶8D)条件下,相互作用的瓢虫的猎物消耗量和利用率为最佳。

【Aim】Indian subcontinent is amongst the vulnerable geographical landscapes of the world. A slight fluctuation in its climatic conditions may adversely influence its seasonal cycles and may cause a tremendous outbreak of aphids in its agroecosystems. Coccinella septempunctata L. and C. transversalis Fab.（ Coleoptera： Coccinellidae） are the two sympatric aphidophagous ladybirds that abundantly inhabit the subcontinent. 【Methods】The present ex-situ study has therefore been designed to explore how the two ladybirds would respond to increasing temperature（ 15,20,25,30 and 35℃） and photoperiod（ 8L∶ 16 D,12L∶ 12 D and 16L∶ 8D） when allowed to feed together on a common prey resource（ pea aphid） in conspecific and / or heterospecific combinations. 【Results】The results revealed that 2-predator conspecific / heterospecific combinations of both the ladybirds exhibited antagonistic effects at five different temperatures and three different photoperiodic conditions. Despite of antagonistic effects,predators in conspecific / heterospecific combinations consumed,converted and utilized the prey biomass maximally at25℃ and under long（ 16L∶ 8D） photoperiodic conditions. However,their consumption rates,conversion efficiencies and growth rates were highest in heterospecific combinations. The 4th instar larvae utilized the prey biomass more efficiently to their own biomass at five different temperatures,while the adult females did the same at three different photoperiodic conditions. 【Conclusion 】 It may therefore be inferred that increasing temperature and photoperiodic conditions might not stop the ladybirds from interacting antagonistically in conspecific and heterospecific combinations,but at 25℃ and under long（ 16L∶ 8D） photoperiodic conditions the prey consumption and utilization efficiency of the interacting ladybirds would be optimum.