Extensive Field Observations Throw Light on the Evolution of Mimicry in <scp> <i>Camponotus lateralis</i> </scp> (Hymenoptera: Formicidae)

The Mediterranean ant-ant association between <i>Camponotus lateralis</i> and <i>Crematogaster scutellaris</i> has fascinated naturalists for long, with a focus on documenting the attraction of <i>Ca. lateralis</i> workers to <i>Cr. scutellaris</i> trails. Little attention, in contrast, has been put on similar behaviors between other <i>Camponotus</i> and <i>Crematogaster</i> species. Moreover, neither the adaptive value of mimicry in <i>Ca. lateralis</i>, which mimics the color patterns of different <i>Crematogaster</i> species, nor its evolution is understood. Data and video records (https://figshare.com/s/b627084f6a7f60e6dc4c) of 2 one-month-long and several short field trips brought insights into this mimicry evolution: We recorded trail following, a behavior hitherto known from four Mediterranean species, from 10 Camponotini species. The percentage of <i>Ca. lateralis</i> workers to those of <i>Crematogaster</i> on trails was only 2.4%. <i>Camponotus lateralis</i>, <i>Ca. ruber</i>, and <i>Colobopsis</i> species were the only trail followers mimicking <i>Crematogaster</i> color patterns. Dealate gynes of <i>Ca. lateralis</i> and <i>Ca. kiesenwetteri</i> founded colonies next to <i>Crematogaster</i> trails. Of 211 <i>Ca. lateralis</i> colonies, 79% were associated with <i>Crematogaster</i>. <i>Camponotus lateralis</i> nests putatively associated with <i>Crematogaster</i> had 2.2 times more workers and a 2.2 times higher chance to produce sexuals. <i>Camponotus lateralis</i> major workers defended entrances against <i>Crematogaster</i> by blocking them with their heads, in a similar manner as <i>Colobopsis</i>. At 15 of 19 sites, lacertid lizards were present; some ingested ants but avoided <i>Crematogaster</i>. Several characteristics of <i>Ca. lateralis</i> concerning its behavior, morphology, colony structure, and nesting site selection are advantageous for the mimicry strategy. Of these, we identified those shared with related non-mimetic species as putative preadaptations. The manifestation of regional color morphs could be the only species-specific mimicry adaptation, while several common characteristics among Mediterranean Camponotini appear as preadaptations to trail following or to mimicry. Trail following facilitates access to food and protection; color mimics likely evolved from non-mimetic trail followers and enjoy reduced predation through Batesian mimicry.