Abstract
Macrolophus pygmaeus (Rambur, 1839) (Insecta, Heteroptera, Miridae) is a predator of key vegetable crop pests applied as a biocontrol agent in the Mediterranean region. Macrolophus pygmaeus and Macrolophus melanotoma (A. Costa, 1853) are cryptic species with great morphological similarity which results in their misidentification and negative consequences for the conservation of their populations on greenhouse and outdoor crops. In order to find out specific markers for their separation we studied the karyotype, male meiosis and heterochromatin composition of these species and additionally of a third species (as a reference one), Macrolophus costalis Fieber, 1858. We demonstrate here that all the three species share achiasmate male meiosis and sex chromosome pre-reduction. On the other hand, the species differ in karyotype, with 2n=28 (26+XY) in Macrolophus pygmaeus, 2n=27 (24+X1X2Y) in Macrolophus costalis, and 2n=34 (32+XY) in Macrolophus melanotoma, and heterochromatin distribution and composition. In addition, the species differ in sperm morphology: sperm cells of Macrolophus costalis are significantly longer with longer head and tail than those of Macrolophus melanotoma and Macrolophus pygmaeus, whereas sperm cells of Macrolophus melanotoma have a longer tail than those of Macrolophus pygmaeus. All these characters can be used as markers to identify the species, in particular the cryptic species Macrolophus melanotoma and Macrolophus pygmaeus.
Highlights
The Miridae are the largest family of true bugs (Heteroptera, Cimicomorpha) with approximately 10000 species described (Schuh 1995)
In order to find out specific markers for their separation we studied the karyotype, male meiosis and heterochromatin composition of these species and of a third species, M. costalis Fieber, 1858
The chromosome formula of male M. costalis was determined as 2n=27 (24+X1X2Y) in contrast to 2n=28 (24+X1X2X3Y) earlier reported in Grozeva et al (2006)
Summary
The Miridae are the largest family of true bugs (Heteroptera, Cimicomorpha) with approximately 10000 species described (Schuh 1995). Cytogenetical data are presently available for about 200 species (Ueshima 1979, Nokkala and Nokkala 1986, Grozeva 2003, Grozeva et al 2006, 2007, Grozeva and Simov 2008a, b, 2009, Kuznetsova et al 2011). The mirid bugs share some cytogenetic characteristics with all the Heteroptera: they possess holokinetic (or holocentric) chromosomes and most of them are characterized by an inverted sequence of reductional and equational division of the sex chromosomes (post-reduction) in male meiosis (Ueshima 1979). In the three hitherto studied Macrolophus Fieber, 1858 species, M. costalis Fieber, 1858, M. pygmaeus (Rambur, 1839) and M. geranii Josifov, 1961, both autosomes and sex chromosomes divide pre-reductionally during the achiasmate male meiosis (Grozeva et al 2006, 2007)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
