Aggressive mimicry in Cretaceous bugs

SUMMARY Mimicry is ubiquitous in nature, yet understanding its origin and evolution is complicated by the scarcity of exceptional fossils that enable behavioural inferences about extinct animals. Here we report bizarre true bugs (Hemiptera) that closely resemble beetles (Coleoptera) from mid-Cretaceous amber. The unusual fossil bugs are described as Bersta vampirica gen. et sp. nov. and B. coleopteromorpha gen. et sp. nov., and are placed into a new family, Berstidae fam. nov. The specialised mouthparts of berstids indicate that they were predaceous on small arthropods and their striking beetle-like appearance implies that they mimicked beetles to attack unsuspecting prey; this unique association is not seen among extant insects and represents the first case of aggressive mimicry in the invertebrate fossil record. This rare example of fossilised behaviour enriches our understanding of the palaeoecological associations and extinct behavioural strategies of Mesozoic insects.摘要：拟态（Mimicry）在自然界中广泛存在，然而由于缺乏可用于推断灭绝动物行为的特异化石，学界对其起源与演化的认知始终错综复杂。我们在此报道产自白垩纪中期琥珀的一类形态与甲虫（Coleoptera）高度相似的怪异半翅目（Hemiptera）昆虫。这些形态特异的化石昆虫被正式描述为两个新属新种（gen. et sp. nov.）：吸血贝斯塔虫（Bersta vampirica）与鞘形贝斯塔虫（B. coleopteromorpha），并被归入全新的贝斯塔虫科（Berstidae）新科（fam. nov.）。贝斯塔虫科昆虫的特化口器表明其以小型节肢动物为捕食对象，而其醒目的甲虫状外形则暗示它们通过拟态甲虫来偷袭毫无防备的猎物；这种独特的生态关联在现生昆虫中从未被发现，同时也是无脊椎动物化石记录中首例被证实的攻击性拟态（aggressive mimicry）案例。这一罕见的化石化行为实例，丰富了我们对中生代（Mesozoic）昆虫古生态关联以及灭绝昆虫行为策略的认知。