Anthophora retusa is a rare solitary bee which has declined throughout Britain and other European countries since the 1990s. It is thought to be restricted to five sites in Britain. However, information on these remaining populations is limited. Knowledge on population size, habitat and forage requirements and foraging distance, are important for successful conservation of species. The population of A. retusa at the Seaford Head Nature reserve in East Sussex was surveyed. Transects within the reserve were conducted and population estimates using mark recapture were made for 2018 and 2019. Pollen from foraging females was analysed alongside visual sightings to determine forage requirements. The total population was estimated to be 91 in 2018 (males and females) with an estimated male population of 167 in 2019. The most visited flower species by females was Glechoma hederacea (66% of visits) but flower preference changed throughout the flight season, shifting to Fabaceae species and Iris foetidissima with 16 plant groups identified in pollen samples. Bees were geographically restricted to a small area within the reserve (approximately 30 ha). Although the exact location of nesting sites was not determined with certainty it is thought nests are in the loess deposits at the top of the inaccessible sea cliff face. This project suggests the presence of appropriate nesting sites may be limiting A. retusa distribution as they appear to forage on common plant species. More research is needed on the exact nesting requirements of the species. The findings from this paper help contribute to the limited understanding of the ecology of this rare and declining species. By knowing the forage requirements of A. retusa, other areas where it is found can ensure these are present within a short distance of nest sites, hopefully ensuring the survival of individual populations and therefore the species.

中文翻译：

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Seaford Head自然保护区珍稀独蜂Anthophora retusa种群评估及觅食生态

Anthophora retusa 是一种罕见的独居蜜蜂，自 1990 年代以来，它在整个英国和其他欧洲国家均已减少。它被认为仅限于英国的五个地点。然而，关于这些剩余种群的信息是有限的。关于种群规模、栖息地和饲料要求以及觅食距离的知识对于成功保护物种很重要。对东萨塞克斯郡 Seaford Head 自然保护区的 A. retusa 种群进行了调查。对保护区内的横断面进行了研究，并使用标记重新捕获对 2018 年和 2019 年的种群进行了估计。 对觅食雌性的花粉进行了分析，并通过目测确定了对饲料的需求。2018 年总人口估计为 91 人（男性和女性），2019 年估计男性人口为 167 人。雌性访问量最大的花卉种类是 Glechoma hederacea（访问量的 66%），但在整个飞行季节中，花卉偏好发生了变化，转向豆科物种和 Iris foetidissima，在花粉样本中鉴定出 16 个植物群。蜜蜂在地理上被限制在保护区内的一小块区域（大约 30 公顷）。尽管尚未确定筑巢地点的确切位置，但人们认为筑巢地点位于人迹罕至的海崖顶部的黄土沉积物中。该项目表明，适当的筑巢地点的存在可能会限制 A. retusa 的分布，因为它们似乎以常见植物物种为食。需要对该物种的确切筑巢要求进行更多研究。这篇论文的发现有助于对这种稀有和衰退物种的生态学有有限的了解。通过了解 A. retusa 的草料需求，发现它的其他地区可以确保它们存在于巢穴附近的短距离内，有望确保个体种群以及物种的生存。