Average Number Of Eggs Research Articles

Ethanol: a better preservation technique for Daphnia

A 4% formalin‐40% sucrose solution has been used by limnologists for three decades as the preferred freshwater zooplankton preservative because it kills and fixes cladocera (Branchiopoda) with relatively little distortion. Because of the increasing evidence of health hazards related to formalin, we sought an alternative, safer preservative that satisfies the need for low distortion. Our results suggest the ethanol preservative methods (70% and 95% treatments) are as good or better as using 4% sugar formalin to fix and store samples. Our results indicate the best method is to fix samples in 95% EtOH followed by storage in 70% EtOH. This technique gave us the least frequent distortion, the highest average number of eggs per female, and the fewest embryos lost from the brood chamber. None of the techniques appeared to have positive or negative effects on body length. Using hot water to fix animals before storage is not recommended.

An Examination of Predatory Pressures on Piping Plovers Nesting at Breezy Point, New York

Abstract This study examines predatory threats to Piping Plovers (Charadrius melodus) nesting at Breezy Point, Gateway National Recreation Area, New York. Several methods used include: 1) an evaluation of reproductive success data with documentation of predation to eggs and chicks, 2) predator surveys, and 3) an artificial nest study. The range of breeding pairs nesting from 1988-1996 was 11-19, with an average of 15.8 (SE ± 0.79) pairs/season. The average number of eggs hatched and chicks fledged per year for pairs was 2.2 ± 0.23 and 0.8 ± 0.16 respectively. Reasons for egg losses often went undetected (68%) but known sources included: tidal flooding (2%), human disturbance (4%), and predation (26%). Reasons for chick loss were generally not detected (99%). For eggs in artificial nests, overall egg removal was 84% and the two main predators based on visible footprints in sand were avian: gulls and crows. Results suggested that gulls predated significantly fewer eggs at artificial nests than crows, althou...

OVIPOSITION BIOLOGY OF ACANTHOCINUS NODOSUS (COLEOPTERA: CERAMBYCIDAE) IN PINUS TAEDA

Oviposition biology of Acanthocinus nodosus was examined on southern pine beetle (SPB), Dendroctonus frontalis, infested loblolly pine trees in Alabama, U.S.A. Components of oviposition biology, including oviposition pit description, colonization period, average number of eggs laid per oviposition pit, use of bark beetle entrance or ventilation holes as oviposition sites, and pit density were described. Acanthocinus nodosus oviposition pits were easily differentiated from Monochamus titillator, another cerambycid species that also inhabits SPB-killed trees. Colonization of trees by A. nodosus began within 2 days of initial SPB attack and lasted for 8 to 14 days. Females laid an average of 3.33 (SE ± 0.48) eggs per oviposition pit and 99% of the pits occurred on SPB entrance and ventilation holes. All pits were on the lower bole between 18 and 163 cm above the ground. Oviposition pit density ranged from 0.22 to 0.45 pits per cm2 of bark surface. Potential interactions with other phloem inhabiting species were noted.

Effect of Temperature on Development, Survivorship, and Fecundity ofLysiphlebia mirzai(Hymenoptera: Aphidiidae), a Parasitoid ofToxoptera citricida(Homoptera: Aphididae)

Development, survivorship, longevity, and reproduction of Lysiphlebia mirzai Shuja-Uddin, a parasitoid of Toxoptera citricida (Kirkaldy), was studied at constant temperatures in the laboratory. Larval development ranged from 8.3 d at 32°C to 20.3 d at 10°C, and pupal development ranged from 3.7 d at 30°C to 15.4 d at 10°C. No adults emerged from mummies at 32°C. Duration of larval development was longer than pupal development. The respective low developmental temperatures and degree-days (DD) were estimated at 3.7°C and 142.7 DD for larval stage, 4.8°C and 94.2 DD for pupal stage, and 6.2°C and 181.2 DD for combined immature stage. The respective optimal temperatures of 30.3, 33.3, and 31.1°C for larval, pupal, and combined immature development were determined from a nonlinear biophysical model. The pupal survivorship was relatively constant within 10–20°C (90–84.5%). The average number of eggs laid per female in the initial 24-h period varied from 106.3 at 25°C to 41.8 at 32°C. The average longevity of L. mirzai adults decreased linearly with increasing temperature. At high (37 and 40°C) and low (5°C) temperature, the average pupal survivorship decreased as treatment time increased. Adult parasitoids failed to emerge from the mummies at 40°C after a 4-h treatment. In addition, the mean longevity of adult parasitoids was enhanced when they were fed with honey and water. The optimal constant temperature range for L. mirzai population growth was 15–25°C. This parasitoid may be more effective in control of brown citrus aphid in cooler months than in summer months.

Influência da temperatura sobre a longevidade, fecundidade e atividade hematofágica de Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) sob condições de laboratório

Influence of temperature on longevity, fecundity, and haematophagic activity of Aedes (Stegomyia) albopictus Skuse, 1894 (Diptera, Culicidae) under laboratory condition. Based on adults of Aedes albopictus maintained under four constant temperatures, 15oC, 20oC, 25oC and 30oC, longevity of males and females, fecundity, eggs viability, number of days from emergence to the first bloodsucking, and duration of the preoviposition period were observed. The average of the longevity for female was 19.45, 59.35, 61.55 and 42.72 days, under 15oC, 20oC, 25oC and 30oC, respectively. The greatest average number of bloodsucking per female was 8.32, under 25oC. The average number of eggs per female was 1.00, 73.91, 269.87 and 183.69, and the greatest rates of viable eggs per female was 25oC and 30oC. The haematophagic activities and the oviposition were significantly influenced by temperature.

Hybrid crosses of the meadow spittlebug Philaenus spumarius (L.) (Homoptera: Cercopidae) between New Zealand and Welsh populations

Crossing experiments with polymorphic meadow spittlebugs Philaenus spumarius (L.), obtained from New Zealand and Wales, were performed. Eight of the total of 18 hybrid crosses set up between the two regions were successful, producing 165 fertile progeny. Some insects mated up to 6 times and stayed up to 24 h in copula. Although the average number of eggs laid per female was 68.5 (range 19–134), the family sizes produced by the crossing experiments ranged between 6 and 56 adult offspring. The pure‐bred flavicollis (FLA) and lateralis (LAT) forms of Philaenus spumarius have not been crossed in previous studies of this species. The two genetically controlled forms, FLA and LAT, which were expressed by the alleles “F” and “L” respectively, were co‐dominant to each other and produced the marginellus (MAR) phenotype in the heterozygous (F/L) combination in both females and males. The FLA, LAT, and two other phenotypes—leucocephalus (LCE) and typicus (TYP)—that appeared in the progeny were also clearly expressed in both sexes.

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Survival, fecundity and insecticide susceptibility of the cat flea, Ctenocephalides felis fed on mice were evaluated. Duration from egg to cocoon formation of C. felis fed on mice was about 8 days, that from egg to adult emergence was about 18 days, and the accumulated emergence rate was 89.2%. The average number of eggs deposited was 10.3 eggs/day/(female), max. egg deposition was 21.6 eggs/day/(female) at 4 days after infestation, and total number of egg deposition was 402 eggs/(female). Longevity of C. felis reared on mice was more than 40 days. Insecticide susceptibility of mouse strain C. felis was the same as that of the cat strain. This rearing method is very simple and useful for producing a large number of cat fleas in a small space.

Effect of acaricide resistance on reproductive ability of the honey bee mite Varroa destructor.

The reproduction of pyrethroid-resistant Varroa destructor mite, a brood parasite of honey bees, was observed in Weslaco, Texas, and the results compared with known susceptible mite populations from other studies. Seven Apis mellifera colonies that had mite populations resistant to the acaricide Apistan were used. Pyrethroid-resistance was confirmed when only 17% rather than 90% of mites confined in dishes containing Apistan died after 12 h of exposure. The average number of eggs laid by resistant mites invading worker and drone cells was 4.4 and 5.4 respectively. This is similar to the number of eggs laid by susceptible mites in worker (4.4-4.8) or drone (4.7-5.5) cells. Also the average number of fertilised V. destructor female mites produced by resistant mites in worker (1.0) and drone (2.1) cells were similar to the number produced by susceptible mites in worker (0.9) and drone (1.9-2.2) cells. In addition, no major differences between the resistant and susceptible mite populations were observed in either worker or drone cells when six different reproductive categories and offspring mortality rates were compared. Therefore, it appears that there is little or no reproductive fitness cost associated with pyrethroid resistance in V. destructor in Texas.

Manipulation of Host Density Affects Infestation of a Peritrich Ciliate (Epistylis lacustris) on a Calanoid Copepod (Leptodiaptomus minutus) in Crystal Lake, Wisconsin, USA

ABSTRACT Specimens of the calanoid copepod, Leptodiaptomus minutus, collected in June 1994 in oligotrophic north temperate Crystal Lake, were infested with the stalked ciliate Epistylis lacustris. E. lacustris was highly specific to L. minutus and no other coexisting zooplankters were infested. Excluding nauplii, nearly 70% of copepods carried 1–20 ciliates, although the maximum load was as high as 250 ciliates. A lower percentage of nauplii were infested by the ciliate; those that were infested had a lower ciliate load than other copepod stages. Infestation by ciliates had no significant influence on the average egg number of female copepods. In a field experiment, higher copepod densities in enclosures resulted in a significantly higher infestation rate, but the ciliate load per individual copepod did not differ significantly among treatments.

Toxicity of select beta adrenergic receptor-blocking pharmaceuticals (B-blockers) on aquatic organisms.

One class of pharmaceutical compounds identified in U.S. and European waters are the B-adrenergic receptor blocking compounds (B-blockers). However, little information is available on the potential aquatic toxicity of these compounds. Therefore, Hyalella azteca, Daphnia magna, Ceriodaphnia dubia, and Oryias latipes (Japanese medaka) were exposed to metoprolol, nadolol, and propranolol to determine potential toxicity. Average 48-h LC(50) for propranolol to H. azteca was 29.8 mg/L. The no-observed-effects concentration (NOEC) and lowest-observed-effects concentration (LOEC) for propranolol affecting reproduction of H. azteca were 0.001 and 0.1 mg/L, respectively. The average propranolol and metoprolol 48-h LC(50)s for D. magna were 1.6 and 63.9 mg/L, respectively. C. dubia 48-h LC(50)s were 0.85 and 8.8 mg/L for propranolol and metoprolol, respectively. The NOEC and LOEC of propranolol affecting reproduction in C. dubia were 0.125 and 0.25 mg/L, respectively. In O. latipes, the propranolol 48-h LC(50) was 24.3 mg/L. Medaka growth was decreased at 0.5 mg/L propranolol. A 2-week medaka reproductive study indicated significant changes in plasma steroid levels; however, no changes in the average number of eggs produced or number of viable eggs which hatched was observed. In a 4-week follow-up propranolol exposure, the total number of eggs produced by medaka and the number of viable eggs that hatched were decreased at concentrations as low as 0.5 microg/L. Based on this study and the expected aqueous environmental exposure levels, adverse effects of propranolol to invertebrate populations is unlikely; however, further reproductive studies are need to elucidate the risk to teleosts.

A comparison of in vitro fertilization (IVF) success rates in non obstructive azoospermia (NOA) with fresh (FRTB) and cryopreserved (FZTB) testicular tissue.

Objective: We have previously shown that IVF pregnancy results with fresh testicular sperm are superior to frozen epididymal sperm in men with obstructive azoospermia (OA). The sperm in NOA are frequently of a much poorer quality than in OA. We undertook a study to investigate whether the IVF results with cryopreserved testicular sperm differed from those with fresh sperm in NOA. Design: Retrospective chart review. Materials/Methods: Between 1995 and 2000, 52 IVF cycles with intracytoplasmic sperm injection (ICSI) in men with NOA were reviewed. 42 cycles utilized either FRTB or FZTB. We analyzed the outcomes with respect to maternal age (MA), number of eggs produced (EP), fertilization rate (FR), embryo quality (EQ), biochemical pregnancy rate (BPR), fetal heart rate detection rate (FHDR), and delivery rate/ongoing pregnancy rate (DR/OP). Statistical analysis was done with JMP statistical software. Results: The maternal age in both groups favored the FRTB (32 vs 35). The lower MA was reflected in a higher average number of eggs produced (16 vs 10) and a slightly better mean embryo quality (1.6 vs 2.2). Assisted hatching rates were higher in the FRTB group (39% vs 29%). BPR, FHDR and DR/OP rates were comparable. IVF results in NOA with FRTB and FZTB. Tabled 1BCP (%)FHDR (%)DR/OP (%)FRTB10 (36)8 (29)8 (29)FZTB7 (50)4 (29)3 (27)p value0.371.000.44 Open table in a new tab Conclusions: Despite a lower quality sperm in NOA, they appear to survive cryopreservation. Pregnancy results with cryopreserved sperm are comparable to those with fresh testicular sperm. Our data suggest that when retrieving sperm during fresh biopsies an attempt at sperm cryopreservation should be made in men contemplating possible future cycles. Testicular preservation is important in these men with limited testicular reserve.

Characteristics of the biological cycle of Lutzomyia evandroi Costa Lima & Antunes, 1936 (Diptera: Psychodidae) under experimental conditions.

Lutzomyia evandroi Costa Lima and Antunes, 1936 is found in Rio Grande do Norte, northeastern Brazil, in areas of visceral and mucocutaneous leishmaniasis and follows the same geographic distribution of L. longipalpis. The biological cycle, oviposition, morphological and behavioral characteristics of the species were studied under experimental conditions. The average number of eggs per wild caught female varied from 21 to 50 eggs along the year, with a peak occurring between January and March and another in August, with oviposition lasting for 4 to 12 days. The mean larval phase was 24 days. Ovipositing rates were influenced by rainfall and temperature indexes, with an increase of eggs per oviposition at the beginning and at the end of the rainy season, and a decrease at the peak of the rainy season.

Culicoides arakawae (Diptera: Ceratopogonidae) efficiently blood-fed and infected with Leucocytozoon caulleryi through a natural membrane

Culicoides arakawae, the most common Culicoides sp. on chicken farms in East Asia, is an important blood-sucking insect and Leucocytozoon caulleryi vector. How parasites, in an ingested blood bolus, enter the midgut of insects and deal with this complex and biochemically hostile environment is poorly understood. However, successful blood-feeding through a membrane in C. arakawae is beneficial for studying this phenomenon. Therefore, a membrane-feeding method for C. arakawae was developed in. The blood-feeding success rates of C. arakawae fed through five different membranes were: turkey egg at 43.7±11.7%, chicken egg at 45.2±12.1%, duck egg at 38.8±12.0%, pig gut at 0% and chick skin at 0%. In fertility measurements, the average number of eggs produced for C. arakawae fed through egg-shell membrane, at 77.7±15.1 per female, was significantly higher ( P<0.01) than the 46.7±10.6 found in C. arakawae fed on the breast skin of a live chicken. Meanwhile, in parasite infectivity tests, C. arakawae could be infected by L. caulleryi when the vector was blood-fed with infective blood cells reconstituted with specific pathogen-free (SPF) sera through an egg-shell membrane. The sporozoite average and infection rates of inoculated chicks were 166.8±12.5 and 100%, respectively. In conclusion, feeding C. arakawae blood through fowl-egg-shell membranes should be an efficient method for in vitro infection of midges as the engorged midges are infected by parasites and display reproductive potential. Furthermore, the method is practical for feeding a large number of midges.

Current prevalence of adult Uncinaria spp. in northern fur seal ( Callorhinus ursinus) and California sea lion ( Zalophus californianus) pups on San Miguel Island, California, with notes on the biology of these hookworms

A prevalence survey for hookworms ( Uncinaria spp.) was done in northern fur seal ( Callorhinus ursinus) and California sea lion ( Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 fur seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 ( x ̄ =760 ) in fur seal pups and from 20 to 2634 ( x ̄ =612 ) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live fur seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of fur seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a fur seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.

Harlequin bug, Murgantia histrionica (Hahn) (Heteroptera: Pentatomidae) development on three crucifers and feeding damage on broccoli

Laboratory studies were conducted to evaluate harlequin bug, Murgantia histrionica (Hahn), development on broccoli, mustard, and rape, and feeding damage on broccoli. Duration of the first stadium was 4.9±0.6 days. Development times of the second through fifth instars reared on broccoli, mustard, and rape were not significantly different. However, preoviposition periods were shorter for nymphs reared on rape, 19.5±0.9 days, compared with mustard, 24.6±1.0 days. The average number of eggs per female (149) reared on broccoli had a hatch rate of 71%. Harlequin bug feeding damage was evaluated on broccoli with 5, 6, and 7 pairs of leaves. Densities of 3, 6, 9, and 12 bugs per plant were placed on broccoli with 6 or 7 pairs of leaves. Plants with 5 pairs of leaves were subjected to densities of 2, 4, 6, and 8 bugs per plant. Feeding damage resulted in death of all plant ages tested. The younger plants succumbed to feeding injury sooner than the older plants, and time to death of plants decreased as insect density increased. This trend was more apparent for broccoli plants with 7 pairs of leaves (20 cm tall), than the younger plants.

Laboratory Studies on the Biology of Culiseta longiareolata (Macquart) (Diptera: Culicidae)

Biological studies were conducted on Culiseta longiareolata (Macquart) at different temperatures and on several hosts. Tests on potential hosts were conducted on man, human blood, and on the house sparrow at room temperature. Adults fed on the house sparrow, human blood, but did not feed on man. At 25 ± 1°C, the average incubation period was 2.0, 3.1, 3.5 and 2.1 days; the average hatching % was 96.2, 96.5, 91.3 and 97.6; the average number of eggs per egg-raft was 165.9, 184.5, 48.9 and 240.2 for females fed on pigeons, house sparrow, human blood and for field egg-rafts, respectively. Average larval duration was 9.0, 11.0 and 9.7 days and the average duration for pupae was 2.7, 3.0, and 2.7 days for larvae obtained from females fed on pigeons, and larvae obtained from females fed on the house sparrow, respectively. The average duration of adult stage was 37.4 days. Average preoviposition period for females fed on pigeons was 3.0 days, while it was 11.1 and 11.8 days for females fed on house sparrow and human blood. At 15 ± 1°C, the average incubation period was 4.04 and 4.08 days and the average hatching % was 97.7% and 97.9%, for females fed on pigeons and for field egg-rafts, respectively. The average duration of larval stage was 19.8 and 22.1 days, and for pupal stage was 5.8 and 5.5 days, for field larvae and for larvae obtained from females reared on pigeons, respectively. The average duration of adult stage was 49.2 days. The average preoviposition period for females fed on pigeons was 12.04 days. Some observations on the behavior of this species were recorded at room temperature.

Effects of temperature on biology and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae)

SummaryThe development, survivorship, longevity, reproduction, and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama were evaluated at 10°C, 15°C, 20°C, 25°C, 28°C, 30°C and 33°C. The populations reared at 10°C and 33°C failed to develop. Between 15°C and 30°C, mean developmental period from egg to adult varied from 49.3 days at 15°C to 14.1 days at 28°C. The low‐temperature developmental thresholds for 1st through 5th instars were estimated at 11.7°C, 10.7°C, 10.1°C, 10.5°C and 10.9°C, respectively. A modified Logan model was used to describe the relationship between developmental rate and temperature. The survival of the 3rd through 5th nymphal instars at 15–28°C was essentially the same. The mean longevity of females increased with decreasing temperature within 15–30°C. The maximal longevity of individual females was recorded 117, 60, 56, 52 and 51 days at 15°C, 20°C, 25°C, 28°C and 30°C, respectively. The average number of eggs produced per female significantly increased with increasing temperature and reached a maximum of 748.3 eggs at 28°C (P&lt;0.001). The population reared at 28°C had the highest intrinsic rate of increased (0.199) and net reproductive rate (292.2); and the shortest population doubling time (3.5 days) and mean generation time (28.6 days) compared with populations reared at 15–25°C. The optimum range of temperatures for D. citri population growth was 25–28°C.

Rearing of Lymnaea columella (Say, 1817), intermediate host of Fasciola hepatica (Linnaeus, 1758).

The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7 degrees C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory

Is Blastocyst ET Better Than Day 3-ET With Assisted Hatching in the Older Patient?

Objective: Blastocyst transfer (BT) is gaining general acceptance as an effective modality to achieve pregnancy while decreasing the risk of high order gestations. We have recently reported increased pregnancy rates with BT compared to Day 3 embryo transfer (D3-ET) in good prognosis patients under age 40. It remains to be seen if BT is indicated in older women and whether it offsets the potential advantage of assisted hatching (AH) with D3-ET. In this study we compare cycle outcomes in similar populations of women over 40 years who had BT versus D3-ET with AH. Design: Retrospective study. Materials and Methods: Since 1998, patients with >3 eight-cell embryos on day 3 were offered BT. To date, 45 such cycles were in women over 40, of which 26 chose BT. The remaining 18 cycles who had D3-ET with AH along with 8 similar cycles in 1997 formed the comparison group. During this period, 146 blastocyst transfers occurred in women under age 40 who met these same criteria. All patients used their own eggs for IVF (±ICSI). P1 + 10% SSS (Irvine Scientific) was used until day 3; embryos were transferred to Blastocyst medium (Irvine Scientific) + 10% SSS for the BT group. ET was performed by the same physician using a Tefcat catheter. Implantation was defined as an ultrasound documented gestational sac and a viable pregnancy as fetal cardiac activity. Results: The age range was 40–44. The mean age in the BT group was 40.9 compared to 41.6 in the day 3 group. There were no differences in average number of eggs harvested (14.4 for BT v. 12.3 for D3-ET) or in eight cell embryos on day 3 (6.2 v. 5.4.) Only one patient in the BT group arrested at the 8-cell stage and had no embryo transfer. Significantly less embryos were transferred per cycle with BT (2.5) than with day-3 ET (6.5); p<0.001. The implantation rate with BT was 12% (8/66) compared to 5% for day-3 ET (8/170); p=0.07. Viable pregnancy rates for BT were similar (23%, 6/26) compared to day-3 ET (19%, 5/26); p>0.1. This compares to a rate of 60% (87 of 146 cycles) in women under 40 undergoing BT at our center. Conclusions: In older patients with good embryos, the yield of blastocyst formation is reassuring (26/27 cycles) but their pregnancy rate remains significantly lower than their younger counterparts. D3-ET with AH does not appear to improve outcome compared to BT. This justifies extending embryo culture to day 5. While BT may help limit the number of embryos transferred, the very rare occurrence of high order multiple gestation in older patients makes eliminating this risk a low priority. However, older women may benefit from information extended culture gives them regarding their egg quality which may guide them in decisions for future therapy.

The life cycle of Rhipicephalus bursa Canestrini and Fanzago, 1877 (Acarina: Ixodidae) under laboratory conditions

The biology of Rhipicephalus bursa has not been thoroughly studied. In the present study R. bursa was bred in the laboratory and its biology worked out. Larvae, nymphs and adult Rhipicephalus bursa ticks were fed on sheep and were held at 28±1°C and 89±1% relative humidty (RH) in a darkened incubator. The average weight of engorged females was 0.676 g (range 0.353–1.128). The average weight of eggs laid by females was 0.344 g (range 0.146–0.554 g). The average number of eggs laid was 7527 (range 6263–8860) and this was significantly correlated with the weight of the females. The index of Reproduction Efficiency (number of eggs per g weight of female) was 8469.6. The index of Conversion Efficiency (weight of eggs per weight of female) was 0.5037. Peak daily oviposition, at an average of 840 eggs per female, occurred on the 6th day of ovipostion. After Day 6, the rate declined steadily. The average duration of the preoviposition period was 5.1 days (range 4–7 days). The oviposition period averaged 16.5 days (range 12–21 days), and was significantly related to both the weight of the female and the number of eggs laid. The average pre-hatching period was 31.2 days (range 24–45 days). The average feeding time of larvae and nymphs of this two host tick was 15.2 days (range 14–18 days). Female ticks fed for 5.9 days on the average. Heavier nymphs produced females and a shorter premoult period was noted for lighter male nymphs. The males/females ratio was 1.38:1. The time taken to complete the life cycle was on average 142.45 days (range 99–254 days).