Schwarz Melbert, Tokuda Gaku, Osaki Haruka, Mikaelyan Aram
Department of Entomology and Plant Pathology, North Carolina State University, 100 Derieux Place, Raleigh, NC 27695, USA.
Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the Ryukyus, Nishihara-cho, Okinawa 903-0213, Japan.
Insects. 2023 Sep 14;14(9):768. doi: 10.3390/insects14090768.
Cockroaches of the subfamily Panesthiinae (family Blaberidae) are among the few major groups of insects feeding on decayed wood. Despite having independently evolved the ability to thrive on this recalcitrant and nitrogen-limited resource, they are among the least studied of all wood-feeding insect groups. In the pursuit of unraveling their unique digestive strategies, we explored cellulase and xylanase activity in the crop, midgut, and hindgut lumens of and . Employing Percoll density gradient centrifugation, we further fractionated luminal fluid to elucidate how the activities in the gut lumen are further partitioned. Our findings challenge conventional wisdom, underscoring the significant contribution of the hindgut, which accounts for approximately one-fifth of cellulase and xylanase activity. Particle-associated enzymes, potentially of bacterial origin, dominate hindgut digestion, akin to symbiotic strategies observed in select termites and passalid beetles. Our study sheds new light on the digestive prowess of panesthiine cockroaches, providing invaluable insights into the evolution of wood-feeding insects and their remarkable adaptability to challenging, nutrient-poor substrates.
扁鳖亚科（蜚蠊科）的蟑螂是少数以腐朽木材为食的主要昆虫类群之一。尽管它们独立进化出了在这种难处理且氮含量有限的资源上生存的能力，但它们却是所有以木材为食的昆虫类群中研究最少的。为了探究它们独特的消化策略，我们研究了[两种蟑螂名称未给出]嗉囊、中肠和后肠腔中的纤维素酶和木聚糖酶活性。利用Percoll密度梯度离心法，我们进一步对肠腔液进行了分级分离，以阐明肠腔中的活性是如何进一步分配的。我们的研究结果挑战了传统观念，强调了后肠的重大贡献，后肠约占纤维素酶和木聚糖酶活性的五分之一。与颗粒相关的酶（可能源自细菌）在后肠消化中占主导地位，类似于在某些白蚁和扁甲科甲虫中观察到的共生策略。我们的研究为扁鳖亚科蟑螂的消化能力提供了新的见解，为以木材为食的昆虫的进化及其对具有挑战性的、营养贫乏的底物的显著适应性提供了宝贵的认识。
