{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T16:56:33Z","timestamp":1778691393413,"version":"3.51.4"},"reference-count":52,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,4,24]],"date-time":"2020-04-24T00:00:00Z","timestamp":1587686400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"LIFE+ Biodiversity Programme of the European Commission","award":["LIFE U-SAVEREDS Project (LIFE13 BIO\/IT\/000204)"],"award-info":[{"award-number":["LIFE U-SAVEREDS Project (LIFE13 BIO\/IT\/000204)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The reproductive cycle of an invasive alien Italian grey squirrel population was studied to understand its adaptation and limit its spread, in order to conserve the autochthonous red squirrel. Female and male genital traits were evaluated throughout the reproductive cycle, including the ovary, uterus, testicle, epididymis, seminiferous tubule morphometry, and germinative epithelium histology. Moreover, individual female fecundity was determined by counting uterine scars. Ovary width and uterus weight, length, and width reached their highest values in the luteal and pregnancy phases. On conducting a histological evaluation of the testicular germinal epithelium, four morphotypes related to the different reproductive phases of the male squirrels were identified: immature, pubertal, spermatogenesis, and regressive. Testicle and epididymis weights and seminiferous tubule diameters reached their largest values during spermatogenesis. Uterine scar analysis showed that 69% of the females had given birth to one or two litters, while 31% had no uterine scars. Litters were larger in the first breeding period than in the second; annual fecundity was 4.52 \u00b1 1.88 uterine scars\/female. Umbrian grey squirrels have adapted to their non-native range, showing two annual mating periods at times similar to those in their native range, and high reproductive success.<\/jats:p>","DOI":"10.3390\/ani10040738","type":"journal-article","created":{"date-parts":[[2020,4,24]],"date-time":"2020-04-24T11:42:14Z","timestamp":1587728534000},"page":"738","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Reproductive Traits of an Invasive Alien Population of Grey Squirrel (Sciurus carolinensis) in Central Italy"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1727-4118","authenticated-orcid":false,"given":"Margherita","family":"Maranesi","sequence":"first","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonello","family":"Bufalari","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6451-3751","authenticated-orcid":false,"given":"Cecilia","family":"Dall\u2019Aglio","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniele","family":"Paoloni","sequence":"additional","affiliation":[{"name":"OIKOS Institute, Via Crescenzago 1, 20134 Milano MI, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8765-8750","authenticated-orcid":false,"given":"Giulia","family":"Moretti","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silvia","family":"Crotti","sequence":"additional","affiliation":[{"name":"Experimental Zooprophylactic Institute of Umbria and Marche \u201cTogo Rosati\u201d, via Gaetano Salvemini, 1, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3680-0926","authenticated-orcid":false,"given":"Elisabetta","family":"Manuali","sequence":"additional","affiliation":[{"name":"Experimental Zooprophylactic Institute of Umbria and Marche \u201cTogo Rosati\u201d, via Gaetano Salvemini, 1, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marica","family":"Stazi","sequence":"additional","affiliation":[{"name":"Experimental Zooprophylactic Institute of Umbria and Marche \u201cTogo Rosati\u201d, via Gaetano Salvemini, 1, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesca","family":"Bergamasco","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2155-4742","authenticated-orcid":false,"given":"Deborah","family":"Cruciani","sequence":"additional","affiliation":[{"name":"Experimental Zooprophylactic Institute of Umbria and Marche \u201cTogo Rosati\u201d, via Gaetano Salvemini, 1, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonio","family":"Di Meo","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cristiano","family":"Boiti","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2476-5097","authenticated-orcid":false,"given":"Massimo","family":"Zerani","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8799-1200","authenticated-orcid":false,"given":"Francesca","family":"Mercati","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Perugia, via San Costanzo 4, 06126 Perugia PG, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Clavero, M., and Garc\u00eda-Berthou, E. 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