Birke A, Aluja M
Clúster Científico y Tecnológico BioMimic, Instituto de Ecología A.C.,Apartado Postal 63, 91070 Xalapa, Veracruz,Mexico.
Bull Entomol Res. 2018 Oct;108(5):674-684. doi: 10.1017/S0007485317001213. Epub 2017 Dec 4.
The preference-performance hypothesis (PPH) has widely been used to explain host exploitation patterns by phytophagous insects. However, this hypothesis often fails in the case of polyphagous species when compared with specialists. One explanation, validated by the information-processing hypothesis (IPH), considers that polyphagous insects are unable to process a large array of cues, which hinders females from distinguishing between high- and low- quality hosts. Here we analyzed Anastrepha ludens female host preference and offspring performance, and tested if neuronal limitations could possibly play a role in the incapacity of the polyphagous A. ludens to make 'accurate decisions' and therefore partially explain mismatches related to PPH. Results testing the PPH by correlating female preference to six naturally occurring hosts and its offspring outcomes show that A. ludens females oviposited greater proportions of eggs on fruit according to hierarchical preferences. Infestation level was low in white sapote, the preferential and seemingly putative ancestral host, likely due to sapote defence mechanisms. Pupal weight and adult size were lower when A. ludens larvae developed in guava (conditional host that was artificially infested) and peach, a lower ranked host compared with 'Marsh' grapefruit, white sapote, and 'Manila' mango (three preferred hosts). Larvae reared in 'Manzano' pepper, a low-ranked host, performed better than in peach and guava. Results testing the IPH, show that polyphagous A. ludens females were less accurate when discerning between a non natural host (guava) when compared with a preferred, natural host (grapefruit): error rate was significantly higher, number of oviposited fruit in a 6-h period was extremely low, time searching and ovipositing took longer, and pupae recovery was extremely low. Our findings indicate that both hypotheses tested are complementary and help better understand host use by A. ludens. However, we also discuss the complexity of polyphagy considering other factors such as plant resistance/defence mechanisms which are not fully addressed in both theories tested.
偏好-表现假说（PPH）已被广泛用于解释植食性昆虫对寄主的利用模式。然而，与专食性物种相比，这一假说在多食性物种的情况下往往不成立。一种由信息处理假说（IPH）验证的解释认为，多食性昆虫无法处理大量的线索，这阻碍了雌虫区分高质量和低质量的寄主。在此，我们分析了加勒比按实蝇雌虫的寄主偏好和后代表现，并测试了神经元限制是否可能在多食性的加勒比按实蝇无法做出“准确决策”中起作用，从而部分解释与PPH相关的不匹配现象。通过将雌虫偏好与六种自然存在的寄主及其后代结果相关联来测试PPH的结果表明，加勒比按实蝇雌虫根据等级偏好将更大比例的卵产在果实上。在优先且看似假定的原始寄主人心果上，侵染水平较低，这可能是由于人心果的防御机制。当加勒比按实蝇幼虫在番石榴（人工侵染的条件寄主）和桃子中发育时，蛹重和成虫大小较低，桃子是比“马什”葡萄柚、人心果和“马尼拉”芒果（三种偏好寄主）等级更低的寄主。在等级较低的寄主“曼萨诺”辣椒中饲养的幼虫，其表现优于在桃子和番石榴中的幼虫。测试IPH的结果表明，与偏好的自然寄主（葡萄柚）相比，多食性的加勒比按实蝇雌虫在辨别非自然寄主（番石榴）时准确性较低：错误率显著更高，6小时内产卵的果实数量极低，搜索和产卵时间更长，蛹的回收率极低。我们的研究结果表明，所测试的两种假说相互补充，有助于更好地理解加勒比按实蝇对寄主的利用。然而，我们也讨论了多食性的复杂性，考虑了其他因素，如植物抗性/防御机制，而这两种测试理论均未充分涉及。
