دراسة تشخيصية وحياتية لعلقة المياه العذبة Dina punctata Johansson, 1927 (Erpobdellidae : Hirudinea في اهوار السويب من محافظة البصرة جنوب العراق == Identification and Biological study of the Freshwater Leech Dina punctata Johansson, 1927 (Erpobdellidae : Hirudinea) in AL - Swaib Marshes From Basrah province south of Iraq
Author name:
ازهر محمد غالي الخزعلي
General topic:
Biology
Specific topic:
Zoology - Invertebrates
Degree:
Doctorate
University:
University Of Basrah - College Of Education For Pure Sciences
Language:
Arabic
University location:
Basrah
First pages:
24T3585 - p.pdf
Abstract:
The species Dina punctata is recorded for the first time in Iraq (from Al - Swaib marshes). The identification was conducted morphologicaly and molecularly characteristics. The morphological features summarized as : - - The species D. punctata has vermiform body compressed ventrally, ranging in length from 55 - 60 mm and in diameter from 0.5 - 2 mm. The individuals have a large ability for extening. The pointed anterior end carries small anterior sucker which resembles lips surrounding the mouth opining, while the rounded posterior end carries large rounded posterior sucker. - This species is characterized by heterogeneous features such as the color of the body which changes from blackish gray for Adults to dark brown for Juveniles, as well as the number and arrangement of eyes which is in general four pairs arranged as reverse U shape located on the dorsal anterior edge. The first two pairs of eyes are located on the middle line of the body while the third and the fourth pairs are each located on one side of the body behind the anterior pairs. - The body consists of 34 segments, each of them is divided to five secondary annuli. The fifth annuli of each segment is divided into two subsections, thus the main segment becomes consist of six annuli. - The male and female gonopores are open on the ventral surface of the 12th segment, separated from each other by two annuli, the male gonopore is usually larger and clearer and located forward in the middle of the groove which is separate the annuli b2 and a2 respectively. The female gonopore is smaller and located in the back of the male gonopore in the middle of the groove which is separate the b5 and b6 annuli respectively.Because of the instability in some morphological features, the species D.punctata also identified in the present study according to genetic features.During the genetic study, the region of internal transcription space (ITS2) in DNA was isolated from leech specimens by using special primers for region internal transcription space (ITS2), after isolation, the ITS2 genes are amplified.The results of polymerase chain reaction of DNA were obtained of single bands of 580 base pairs molecular weight for all degrees of hybridization. The sequence of each sample after detecting was entered in the database of National Center Biological Information (NCBI) and the result showed that the sequences of all samples are belonging to the species D. punctata. In the field study, monthly samples of leeches D. punctata was collected from the marshes of Al - Swaib on the eastern side of Shatt Al - Arab river inQurna northern Basrah Province during the period from January 2015 to December 2015. A total of 235 individuals and 623 Cocoon were collected during the study period. The highest number was 58 recorded for individuals during May 2015, while being 335 recorded for cocoons during February 2015. On the other hand there is no occurrence recorded during July - August for individuals, and June - November for cocoons.The study investigates the water temperature, salinity and abundance of individuals and cocoons. The statistical analysis showed negative correlation between temperature and abundance of both individuals and cocoons, while the correlation of salinity was slightly positive with abundance of individuals and cocoons.The study of population sizes structure showed that the size class 40 - 50 mm has the highest frequency during the study period compared with the other size classes. On the other hand, the highest percentage of frequency was 66.7%, which also recorded for the size class 40 - 50 mm.Laboratory experiments showed that the members of a species D.punctata able to tolerate saline concentrations between 2 - 6 psu the survival rate 100%, Also, these worms (D. punctata) feed by different ways, it can be considered Predatory Macrophagous and Scavengers, its food materials consist of invertebrate animals such as Oligochaetes, Lumbriculids, Chironomid larvae; fleshy body of some aquatic snails; and on dead fishes. In the laboratory, the leeches fed well on flesh and livers of chicken, sheeps and caws, The laboratory also studied, Three different types of food effect (chicken liver, zooplankton, and animal feed) on the growth of young leech for a period of six weeks.From the field and laboratory observations, the specie D. punctata reproduces sexually by cross fertilization. The male and female gonopores are easily observed in adults which ranging in length from 45 - 60 mm. as well as the sperm sacs on the mid ventral surface of the body during the reproduction season, which extend in our study during two periods : January - May and December 2015. The sexual reproduction processes were studded in detail and the embryonic development in cocoons was divided into five hypothetical stages according to morphological and anatomical changes and these stages are : - 1 - Depositing Cocoon Stage.2 - Primary Cleavage stage.3 - Development and extension.4 - Differentiation of regions stage.5 - Complement and release stage. The histological structure of the body wall, suckers, reproductive organs and digestive tract of adult leeches were investigated. The body wall consists of thick layers of circular, longitudinal and oblique muscles.The structures of the male reproductive system such as genital atrium, sperm sacs and testis were observed. There are two lateral blood sinuses around the mouth cavity in addition to many nerve cells. The posterior sucker is muscular, and the muscle cells are as a dense net in the peripheral part, while are as a loose cells in the middle what give it a sponge appearance, in addition to primitive glomerular cells, nerve cells and mucus cells
