Rapid Assessment of Maturation Stage and Reproductive Mode in Centrolecytic Eggs of Stick Insects (Phasmatodea) Using DAPI Stain

A rapid three-step DAPI technique is proposed for detecting meiotic stages and sperm head evolution in yolky, fertilized stick insect eggs, which were difficult to analyze with other methods. Fixed eggs were freed from chorionic envelopes and stained directly in DAPI/PBS solution. After rinsing, eggs were singly squashed in a drop of mounting buffer and examined under a microscope with incident fluorescent illumination. The method was almost uniformly successful, and direct observation of nuclear structures, coupled with fluorometry, allowed easy recognition of bivalents, diads, pronuclei and their DNA content. The DAPI method proposed here appears particularly helpful for investigating unusual reproductive modes in eggs with large amounts of yolk.     

Résultats hémodynamiques et cliniques de la dissection, assistée par lunettes chirurgicales, des veines spermatiques au niveau de l’orifice inguinal interne

Inversion of venous flow is well visualized by colour duplex ultrasound and is the basic haemodynamic feature of varicocele. We tried to assess the value of dissection of branches of the spermatic vein in the internal inguinal ring using an operating microscope with a magnification of 4.5x. 16 patients were operated according to the ultrasound classification proposed by Hirsh et al. [8]. Varicocele was grade III in 2 cases, grade IV in 11 cases and grade V in 3 cases and was situated on the left in 13 patients and on the right in 3 patients. The diagnosis was based on clinical examination and colour duplex ultrasound. The operating time was 25–35 min. The incision was 1.5 to 2 cm long. No short-term complications or long-term hydrocele were observed. No reno-spermatic flow was observed on colour duplex ultrasound after six months. The mean testicular volume was 22 ml before surgery and did not change after the operation. This surgical technique is less invasive than the conventional retroperitoneal or laparoscopic procedures, and the incision is smaller than with the percutaneous technique. It is less radical than conventional microsurgery, but the operating time is shorter, and the surgical wound is smaller, sparing the artery and lymphatic vessels. In conclusion, this operation can be considered to be a good option in the surgical treatment of varicocele in view of its low complication rate, the absence of hydrocele, a minimally invasive procedure and the good haemodynamic results.     

Mimicry in the burnet moth Zygaena ephialtes: population studies and evidence of a Batesian—Müllerian situation

Abstract. 1. Population size as well as the absolute and relative frequencies of the phegea and filipendulae mimetic complexes have been estimated in an area of Central Italy selected because it is: (a) little affected by man, (b) representative of many others in the Central Appennines, and (c) containing an abundant population of Zygaena ephialtes.
2. This distasteful polymorphic species belongs, in Central Italy as in other Southern areas, to the phegea complex ( Zygaena ephialtes , yellow ephialtoid form), while in Northern and Central Europe it belongs to the filipendulae complex ( Z.ephialtes , red peucedanoid form).
3. In the Southern areas the phegea complex is much more abundant than the filipendulae one, which gives the yellow ephialtoid form of Z.ephialtes a strong mimetic advantage over the red peucedanoid.
4. In addition, Amata phegea greatly outnumbers the other distasteful members of its complex and emerges first.
5. Throughout its flight period Z.ephialtes , which emerges about 20 days later than A.phegea , never attains a frequency higher than 0.03 in this complex. It is suggested that in such a situation the protection that this species gains as a mimic would be very high regardless of its unpalatability.
6. These findings and others discussed in the present paper, such as the degree of unpalatability, the genetics of the mimetic form as well as the polymorphism for colour and pattern, are examined according to the hypothesis of divergent evolutionary strategies in Batesian and Müllerian mimicry. It is suggested that these are meaningful concepts but that individual mimics, of which Z.ephialtes is one, can fall between them.     

Reoccurring neural stem cell divisions in the adult zebrafish telencephalon are sufficient for the emergence of aggregated spatiotemporal patterns

Regulation of quiescence and cell cycle entry is pivotal for the maintenance of stem cell populations. Regulatory mechanisms, however, are poorly understood. In particular, it is unclear how the activity of single stem cells is coordinated within the population or if cells divide in a purely random fashion. We addressed this issue by analyzing division events in an adult neural stem cell (NSC) population of the zebrafish telencephalon. Spatial statistics and mathematical modeling of over 80,000 NSCs in 36 brain hemispheres revealed weakly aggregated, nonrandom division patterns in space and time. Analyzing divisions at 2 time points allowed us to infer cell cycle and S-phase lengths computationally. Interestingly, we observed rapid cell cycle reentries in roughly 15% of newly born NSCs. In agent-based simulations of NSC populations, this redividing activity sufficed to induce aggregated spatiotemporal division patterns that matched the ones observed experimentally. In contrast, omitting redivisions leads to a random spatiotemporal distribution of dividing cells. Spatiotemporal aggregation of dividing stem cells can thus emerge solely from the cells’ history.

An interdisciplinary study of the rules governing cell divisions in a population of neural stem cells in the zebrafish brain reveals the existence of aggregated spatio-temporal division patterns of rapid cell cycles in stem cells, and shows that these patterns can be explained by a simple agent-based model relying solely on the cells‘ division history.     

Comparing patterns of geographic variation in cave crickets by combining geostatistic methods and Mantel tests

Geographic variation patterns of biological characters and environmental variables are compared by using a procedure employing multivariate analyses, production of contour maps by the kriging method with enclosed validation of estimates, and Mantel tests to assess the significance of comparisons. As biological material we chose a sample of Dolichopoda cave crickets populations from Central-Southern Italy. The kriging technique provides estimates of the interpolation error for each true and estimated point. This profitable feature offers the opportunity to use, with ascertained levels of confidence, the estimated z -scores for further analysis and to compare data collected within the same area, but not exactly coincident in location or number. In such a way, we were able to use for subsequent comparisons by means of Mantel tests the maximum number of data points for all data sets, which originally differed in sampling sites. The interpretation of the contour maps and their statistical comparison suggested that allozymes and epiphallus shape data sets follow the phylogenetic pathways within the Dolichopoda populations, whereas variation in leg elongation is almost entirely under the control of an environmental gradient, synthetically described by the cave temperature.     

A taxonomic revision of western Eupholidoptera bush crickets (Orthoptera: Tettigoniidae): testing the discrimination power of DNA barcode

The genus Eupholidoptera includes 46 Mediterranean species distributed from Turkey to Greece, Italy and southern France. In the eastern part of its range, Eupholidoptera has been considered to consist of several distinct species, while in the Balkans and Italian peninsula only E. chabrieri has been recognized. However, the status of some Italian populations, confined to particular geographic areas, remains uncertain. To investigate the delimitation of the Italian taxa of Eupholidoptera, we performed both morphological and molecular analyses. Morphological analysis was carried out by considering diagnostic characters usually used to distinguish different taxa, such as the shape of titillators in males and the subgenital plate in females. Molecular analysis was performed by sequencing three mitochondrial genes: 12S rRNA, 16S rRNA, partially sequenced and the entire gene of cox1. Molecular markers were used to infer phylogenetic relationships among the Italian Eupholidoptera species and to reconstruct the historical processes that shaped their current geographic distribution. Results from both morphological and molecular analyses were used to revise the taxonomic arrangement of species. On the whole we were able to distinguish nine lineages of Italian Eupholidoptera, of which E. tyrrhenica sp.n. from Corsica is described as a new species. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:EBD181A0-5263-4880-AC80-66F624506E3A .