Coevolution of spermatozoa and spermathecae in Lonchopteridae (Diptera).

Across the species of spear-winged flies (Diptera: Lonchopteridae) there is a remarkable variation in size of the female reproductive tract, especially of the spermathecae. In this family there are two tubular spermathecae, which are divided into four morphologically and histologically distinct sections of different lengths and functions. The dimensions of the spermathecae and their individual sections were examined across 11 Lonchoptera species and related to the dimensions of the respective spermatozoa. 3D reconstructions from serial sectioning made it possible to include the volume in these considerations, which is a new approach in this context. Results show that the spermathecae are always longer than the respective spermatozoa. There is a highly significant positive linear correlation between the length of the spermatozoa and the length of the spermathecae in total as well as some of the individual spermathecal sections, suggesting a coevolution of these characters. Moreover, the volume of the spermathecae is much larger in those species with longer and more voluminous spermatozoa, but the volume increase is not sufficient to keep constant the number of spermatozoa that fit within. The observed patterns are discussed with respect to their functional and evolutionary implications, including a new hypothesis on the possible selective advantage of increased spermatozoon length.

Variation of sperm size and evolution of giant spermatozoa in Lonchopteridae (Diptera).

Among species of the spear-winged flies (Lonchopteridae) there is remarkable variation in sperm size, with some species producing giant spermatozoa. With a length of 7500 µm and a width of 1.3 µm the spermatozoon of Lonchoptera fallax ranks among the largest known to date. In the present study body size, testis size, sperm size, and spermatid number per bundle and per testis were examined across 11 Lonchoptera species. Results are discussed in terms of how these characters are related with each other and how their evolution affects the resource allocation amongst spermatozoa. Based on some discrete morphological characters and a molecular tree derived from DNA barcodes a phylogenetic hypothesis of the genus Lonchoptera is proposed. The occurrence of giant spermatozoa in Lonchopteridae is compared to convergent occurrences reported in other taxa.

Morphology and ultrastructure of the spermatozoa of Lonchoptera lutea Panzer, 1809 (Diptera: Lonchopteridae).

Lonchoptera lutea males produce giant spermatozoa that are more than 2000 µm long and 1.4 µm wide. Unlike the typical brachyceran spermatozoon, they have a highly asymmetrical cross-section with only a single, albeit very large, mitochondrial derivative and a pair of massive accessory bodies, one of which extends throughout the entire length of the sperm tail. The accessory bodies consist of an electron-dense matrix in which numerous peculiar electron-lucid substructures are embedded. In the mated female, the giant spermatozoa are found inside two tubular spermathecae which are also extremely long, measuring 4000 µm or more.

Complex Collagenous Spherulosis of the Breast Presenting as a Palpable Mass: A Case Report with Immunohistochemical and Ultrastructural Studies.

Collagenous spherulosis is a rare, benign breast lesion occuring in less than 1% of benign breast biopsies. All previously reported cases have been discovered as incidental microscopic findings in association with a range of benign to malignant processes. The authors report the first case of collagenous spherulosis presenting as a palpable mass. Immunohistochemistry and electron microscopy performed on this lesion demonstrated the presence of two cell types: epithelial cells and myoepithelial cells with associated basement membranelike material. Collagenous spherulosis may mimic adenoid cystic carcinoma since the epithelial proliferation and spherule formation in collagenous spherulosis closely resembles the changes in adenoid cystic carcinoma. However, adenoid cystic carcinoma is an invasive lesion that is almost always palpable, while collagenous spherulosis is almost always an incidental microscopic finding. Our case illustrates that collagenous spherulosis can also result in a palpable mass, thus palpability of the lesion cannot be used to differentiate these conditions.