{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T16:26:44Z","timestamp":1780504004639,"version":"3.54.1"},"reference-count":33,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T00:00:00Z","timestamp":1752796800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key R&amp;D Program of China","award":["2022YFC2601601"],"award-info":[{"award-number":["2022YFC2601601"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Insects"],"abstract":"<jats:p>Cobboldia elephantis (Oestridae: Gasterophilinae) is an obligate parasite of the alimentary tract of the Asian elephant, causing gastric myiasis. Current knowledge of its first instar larval morphology has been limited to observations under light microscopy, significantly constraining our understanding of morphological evolution within the genus Cobboldia and the broader subfamily Gasterophilinae. In this study, we provided ultrastructural and three-dimensional characterizations of C. elephantis using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) based on newly hatched first instar larvae. Features of the first instar larva of C. elephantis, which are either unique or shared with C. loxodontis Brauer, 1896, include (i) three pairs of mouthhooks, (ii) posterior spiracles bearing peristigmatic tufts, (iii) anal division with two spine-clusters and a row of elongated spines, and (iv) a planed, button-like sensilla and a sensillum placodeum. We also compared the first instar larval morphology of C. elephantis with that of Cobboldia loxodontis, Gyrostigma rhinocerontis (Owen, 1830), Gasterophilus pecorum (Fabricius, 1794), Portschinskia magnifica Pleske, 1926, and Oestrus ovis Linnaeus, 1758. Species of Gasterophilinae share several unique features of the first instar larva, including (i) an anal division composed of three subdivisions, (ii) spiracular slits on the posterior spiracles, and (iii) conserved positioning of thoracic sensilla. These findings fill a key gap in our knowledge of C. elephantis larval morphology and suggest that these distinctive structures play a role in adaptation to its parasitic lifestyle.<\/jats:p>","DOI":"10.3390\/insects16070733","type":"journal-article","created":{"date-parts":[[2025,7,18]],"date-time":"2025-07-18T11:12:34Z","timestamp":1752837154000},"page":"733","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Morphological Study of First Instar Elephant Stomach Bot Fly Larvae (Oestridae: Gasterophilinae: Cobboldia elephantis)"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-3562-0252","authenticated-orcid":false,"given":"Xingkun","family":"Yang","sequence":"first","affiliation":[{"name":"School of Ecology and Nature Conservation, Beijing Forestry University, Qinghua East Road 35, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhuowei","family":"An","sequence":"additional","affiliation":[{"name":"School of Ecology and Nature Conservation, Beijing Forestry University, Qinghua East Road 35, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chaoyong","family":"Xiong","sequence":"additional","affiliation":[{"name":"Asian Elephant Protection Management Center of Xishuangbanna Dai Autonomous Prefecture, Jinghong 666100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shenming","family":"Tan","sequence":"additional","affiliation":[{"name":"Yunnan Xishuangbanna National Nature Reserve Management Bureau, Jinghong 666100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingwei","family":"Bao","sequence":"additional","affiliation":[{"name":"Wild Elephant Valley Asian Elephants Provenance Breeding and Rescuecenter of Xishuangbanna, Jinghong 666100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fangyi","family":"Zhou","sequence":"additional","affiliation":[{"name":"Wild Elephant Valley Asian Elephants Provenance Breeding and Rescuecenter of Xishuangbanna, Jinghong 666100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meiqin","family":"Liu","sequence":"additional","affiliation":[{"name":"Analysis and Testing Center, Beijing Forestry University, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2285-5048","authenticated-orcid":false,"given":"Liping","family":"Yan","sequence":"additional","affiliation":[{"name":"School of Ecology and Nature Conservation, Beijing Forestry University, Qinghua East Road 35, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6427-7867","authenticated-orcid":false,"given":"Dong","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Ecology and Nature Conservation, Beijing Forestry University, Qinghua East Road 35, Beijing 100083, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6609-0609","authenticated-orcid":false,"given":"Thomas","family":"Pape","sequence":"additional","affiliation":[{"name":"Natural History Museum Denmark, Universitetsparken 15, 2100 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,18]]},"reference":[{"key":"ref_1","unstructured":"Zumpt, F. 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