Mean Preoviposition Research Articles

Biology of Fruit Borer, Helicoverpa armigera (Hubner) on Tomato under Laboratory Conditions

The experiment on biology of fruit borer Helicoverpa armigera (Hubner) was carried out in the Bio-control Laboratory, Department of Entomology, S.V.P.U.A.&T., Meerut. Results showed that the mean pre-oviposition, oviposition and post-oviposition period of fruit borer on tomato lasted for 2.46 ± 0.29, 6.33 ± 0.14 and 1.67 ± 0.14 days, respectively. A female laid on an average 329.40 ± 68.17 eggs. The incubation period was observed to be 3.08 ± 0.32 days on tomato. The first instar larva was very active with body length of 1.54 ± 0.81 mm and body breadth of 0.46 ± 0.05 mm. The larval development completed within 22.45 ± 0.44 days. The duration of each instar on tomato was found to be 2.58 ± 0.26, 3.50 ± 0.14, 3.42 ± 0.26, 3.71 ± 0.28, 4.38 ± 0.16 and 4.83 ± 0.14 days, respectively. The mean pre-pupal period lasted for 2.00 ± 0.24 days on tomato. The mean pupal period lasted for 12.33 ± 0.62 days. Longevity of adult ranged from 8 to 11 days with an average of 9.30 ± 1.25 days in males, while the longevity of female moths ranged from 10 to 14 days with an average of 11.30 ± 1.34 days. The male moth measured 17.79 ± 0.41 mm in length, 35.55 ± 0.92 mm in breadth and the female moth measured 19.76 ± 0.58 mm in length, 40.08 ± 0.99 mm in breadth on tomato. The sex ratio for male and female was 1: 0.76 on tomato. The generation from egg to death of male and female i.e., total life cycle was found to be completed within 39 to 60 days with an average of 50.3 ± 7.51 days and 41 to 63 days with an average of 53.5 ± 7.93 days, respectively.

Females of Halyomorpha halys (Hemiptera: Pentatomidae) Experience a Facultative Reproductive Diapause in Northern Greece.

Simple SummaryIn this study we investigated the oviposition rates and fecundity of females of Halyomorpha halys, by collecting adults soon after they entered their overwintering sites and allowing them to overwinter for 2, 3, 4 and 5 months in natural conditions of Northern Greece. We studied the occurrence of a facultative reproductive diapause in females of this insect in N. Greece by measuring the preoviposition period. According to our results, females of H. halys need an additional time period to exit diapause after they emerge from overwintering sites to mature sexually and start laying eggs. This finding is especially important to assess the possible damage of H. halys to early maturing crops for any forecasting models and thus management strategies.Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a native pest of East Asia that overwinters as an adult in natural and human-made structures. Adult emergence from overwintering sites starts in spring, whereas females produce offspring in early summer on host plants, where most feeding occurs. In this study, we investigated the reproductive physiology of overwintering females of H. halys in Northern Greece, by determining the duration of the preoviposition period and fecundity of individuals that were left to overwinter in natural conditions and were subsequently transferred to chambers with standard conditions monthly, from December 2020 to March 2021. According to our results, overwintering H. halys females do not initiate egg laying once they emerge from overwintering sites, but rather need some additional time to exit diapause and mature reproductively. The mean preoviposition period of overwintering females that were transferred from their overwintering sites to the chambers in December 2020 was 29.0 days, which was significantly longer by 8.3 days than that of females that overwintered until March 2021, and by 13.2 days than the control (26 °C, 60% RH and a 16:8 h light: dark photoperiod). No significant difference among the average number of eggs per egg mass laid by overwintering individuals brought in the chambers in different time intervals and the laboratory colony was observed. However, females that were left to overwinter until March laid a significantly higher number of eggs in total, compared to the ones whose overwintering was disrupted in February. Based on our findings, overwintering females of H. halys experience a facultative reproductive diapause in Northern Greece. Our study was the first to determine the occurrence of diapause of H. halys in N. Greece and our findings could be very valuable for assessing the damage of this pest to early-season crops and designing successful management practices.

Biology of Platynaspis saundersi (Coleoptera: Coccinellidae)

Biology of Platynaspis saundersi (Crotch) was studied under laboratory conditions at the Department of Entomology, Dr YSP University of Horticulture and Forestry, Himachal Pradesh, India. The mean preoviposition period was 7.00± 0.21 days, while the oviposition period was 43.50± 0.35 days. The female lays 130.30± 5.96 eggs and the hatching was 86.32± 3.12%, with incubation period being 5.0± 0.47 days and the larval period was for 12.40± 0.35 days. The observed prepupal and pupal periods were 1.50± 0.48 and 7.50± 0.21 day, with longevity of male and female being 70.00± 2.00 and 79.00± 0.89 days, respectively.

Euseius concordis (chant) (Acari: Phytoseiidae) as a potential agent for the control of yerba mate red mite Oligonychus yothersi (McGregor) (Acari: Tetranychidae)

Oligonychus yothersi (McGregor) (Acari: Tetranychidae), known as yerba mate red mite, is typically found on the abaxial face of leaves, feeding on mesophyll cell contents in yerba mate crops. Euseius concordis (Chant) is a generalist mite, feeding on other mites, pollen, and nectar, and can be a promising control agent of O. yothersi. This study aimed to evaluate development time, reproduction, survival, and sex ratio of this predatory mite when feeding on O. yothersi on yerba mate leaves. A life-cycle study was performed in a climate chamber at 22 ± 1 °C and 12 hours of photophase, 19 ± 1 °C during scotophase, and 70 ± 10% relative humidity. The study started with 36 experimental units, which were examined three times a day during immature development and once during the adult stage to evaluate reproductive parameters. Mean developmental times of egg, larva, protonymph, deutonymph, and egg-adult stages were the following: for females, 2.14 ± 0.15, 1.59 ± 0.12, 1.97 ± 0.11, 2.18 ± 0.13, and 7.88 ± 0.21, respectively; for males, 2.00 ± 0.67, 1.77 ± 0.52, 1.94 ± 0.52, 2.05 ± 0.69, and 7.75 ± 1.08. Mean pre-oviposition, oviposition, and post-oviposition periods were 3.31 ± 0.33, 10.4 ± 0.74, and 1.50 ± 0.28, respectively. Sex ratio was 0.67 and mean life expectancy was 15.22 days for females and 12.51 ± 1.91 days for males. Mean daily oviposition was 1.67 ± 0.08 eggs per female, with a mean value of 20.14 ± 1.42 eggs per female. T, Ro, rm, λ, and DT values were: 16.33, 10.03, 0.14, 1.15, and 4.91, respectively. This study demonstrated that E. concordis is a predator with potential to be used in biological control programs, successfully developing and reproducing when feeding on O. yothersi under laboratory conditions.

Studies on biology of mango leaf webber Orthaga exvinacea (Hampson)

The laboratory studies on biology of mango leaf webber was conducted at the Department of Entomology, College of Horticulture, Bagalkot during 2018-19. The studies revealed that the mean preoviposition, oviposition and postoviposition periods lasted for 2.60±0.52, 4.10±0.74 and 1.90±0.74 days, respectively. The larva moulted six times by passing through seven larval instars. The mean durations of 1st, 2nd, 3rd, 4th, 5th, 6th and 7th instar were 4.80±0.92, 4.65±0.90, 4.41±0.63, 4.16±0.87, 4.52±0.51, 5.20±0.42 and 6.50±0.53 days, respectively with mean total larval period of 42.54±2.53 days. The mean duration of male and female pupal stage were 11.80±0.63 days and 14.30±1.43 days respectively. The mean longevity of adult male and female were 4.10±0.74 days and 5.80±0.42 days, respectively. The total life cycle completed in 58.44±3.90days in male and 62.64±4.59 days in female.

Study on the biology of groundnut bruchid, Caryedon serratus Olivier [Coleoptera: Bruchidae] on stored groundnut in Ganye area, Adamawa State, Nigeria

Abstract. Study on the biology of groundnut bruchid, Caryedon serratus Olivier was carried out in the Laboratory of the Department of Agricultural Technology, Adamawa State College of Agriculture, Ganye, Adamawa State from June to September, 2015. The sex of the bruchid (male and female) was assigned the sub-treatment while the period of development was the main treatment and was replicated three times. The work considered the pre-oviposition stage, incubation stage, larval stage, pupal stage, adult stage and the total life cycle of the bruchid (male and female). The experiment was carried out under Laboratory conditions at 30-35°C temperature and 70-90% relative humidity. After the experiment was established, weekly counting of the total number of eggs laid was carried out at intervals. The results showed that, the mean developmental stages in both female and male bruchids were: 6.50 and 6.00 days; 17.00 and 18.00 days; 13.50 and 13.50 days; 12.00 and 13.50 days; 48.00 and 50.00 days for incubation stage, larval stage, pupal stage, adult stage and total life cycle of the bruchids, respectively. Moreover, the mean pre-oviposition and oviposition stages in female adult bruchid were 1.50 and 5.50 days, respectively.

Biology of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) on eggplant and tomato

The study mainly focussed on monitoring different life stages viz., egg, nymphal instars, pupae and adults. The present investigation revealed that mean pre-oviposition, oviposition and post oviposition period were 1.50 and 3.70; 3.50 and 4.50 and 1.60 and 3.30 days on eggplant & tomato, respectively. Further, three nymphal instars were observed in the life history of B. tabaci with average duration of 3.50 and 5.70, 2.40 and 4.80 and 3.50 and 5.40 days for 1st, 2nd and 3rd instars on eggplant & tomato, respectively. The total mean nymphal period on eggplant and tomato was observed as 9.40 and 15.90 days respectively. In addition, the mean pupal period and adult longevity of B. tabaci on eggplant and tomato was 3.70 and 6.30 and 4.05 and 8.30 days respectively. The total life cycle from egg to adult ranged amid 16.5 to 22.5 days on eggplant while on tomato it lasted amid 29.5 to 38.0 days.

Life cycle of oil palm bunch moth, Tirathabamundella walker Lepidoptera: Pyralidae Reared Under laboratory conditions on artificial diet

Tirathaba mundella Walker is an important pest in many oil palm plantations especially those established on peatland. The life cycle of T. mundella has not been described in detail despite its economic importance. This study aimed to describe the bionomic characteristics of T. mundella, rearing on an artificial diet, at 25 oC. The duration of a complete metamorphosis cycle of T. mundella was about 51.63 ± 3.80 days. The incubation period was the shortest (3.33 ± 0.80 days.), The most detrimental stage of the pest to oil palm is at larval stage, which took 33.90 ± 2.60 days before pupating. The pupal period took about 5 to 11 days with a mean ± SD period of 8.53 ± 1.48 days. The average of the adult’s longevity was about 6.05 ± 1.81 days. There is no statistical difference between the duration of male and female longevity. Adult male and female moths reared in captivity feeded with 10% sucrose solution would mate readily and produce fertile eggs. The mean preoviposition period were 4 days. Successful of rearing T. mundella using artificial diet under laboratory conditions promises laboratory assessment for pesticide development which is less tedious and time consuming than conventional field experiments.

Biology of pink mealybug, Maconellicoccus hirsutus on different hosts and predatory efficiency of Cryptolaemus Montrouzieri and Chrysoperla zastrowi sillemi

Biology studies on the pink mealy bug Maconellicoccus hirsutus (Green) showed the mean preoviposition period of 4.9 days and 5.2 days on mulberry and red pumpkin, respectively. On mulberry the mean fecundity was 513 eggs whereas it was 489 eggs on red pumpkin. The mean hatching was 93.3 and 90.7% on mulberry and red pumpkin, respectively. The life cycle was completed in 41.7 and 38.5 days by female and male, respectively on mulberry and it was 47.1 and 46.2 days, respectively on red pumpkin. The observations on the predatory efficiency showed that both grubs and adults of Cryptolaemus montrouzieri together required a total of 1615.9, 210.8 and 32.8 eggs, nymphs and adults, respectively of M. hirsutus to complete their lifecycle; among its larval stages, the maximum predatory efficiency was observed with the IV instar grub. Similar trend was recorded in the predatory potential of Chrysoperla zastrowi sillemi also and its III instar grub consumed 413.8, 155.8 and 16.6 mealybugs of I, II and III instars of M. hirsutus, respectively.

Biology of Castor Leafhopper Empoasca Flavescens Fabricius

The biology of castor leafhopper, Empoasca flavescens Fabricius was studied in the laboratory of the Department of Entomology, C. P. C. A., S. D. A. U., Sardarkrushinagar during 2012–13. The results revealed that the female inserted eggs into leaf tissue mainly near the midrib and veins at lower surface of leaves. It was very difficult to detect them with naked eyes, but could be marked by a small blister on the leaf surface. The eggs were broad and round at one end and gradually tapered towards the other end. The nymphal stage passed through five instars. The mean nymphal development period of first, second, third, fourth and fifth instars were of 2.17 ± 0.76, 2.50 ± 0.87, 3.33 ± 0.76, 3.70 ± 1.01 and 3.20 ± 0.90 days, respectively. The total nymphal duration was 12.73 ± 2.42 days. The adults were yellowish green, wedge shaped and walked diagonally in characteristic manner. The sex ratio of (male: female) was 1: 1.18 for laboratory culture and 1: 1.35 for field collected population. The mean pre-oviposition, oviposition and post-oviposition periods were 3.12 ± 0.85, 4.16 ± 0.87 and 3.24 ± 0.81 days, respectively. The fecundity was 17.11 ± 1.25 eggs. The average longevity of male and female was 8.83 ± 0.97 and 10.85 ± 1.23 days, respectively. The total duration of life cycle varied from 21 to 34 days with a mean of 28.83 ± 4.54 days in male, and 24 to 38 days (average 32.17± 5.85 days) in female.

Development, Survival, and Fecundity of Amblypelta lutescens lutescens (Hemiptera: Coreidae) on Distinct Phenological Stages of Different Fruit-Crop Host Plants.

The banana-spotting bug, Amblypelta lutescens lutescens Distant (Hemiptera: Coreidae), is native to Australia and a major polyphagous pest of many tropical and subtropical horticultural crops in the east and north of the country. Different plant structures (flowers, vegetative flush, and different sized fruit) of avocado, lime, and papaya crops and green bean pods (a known suitable host) were evaluated for their suitability as hosts for A. l. lutescens Neonate to imago survivorship, the time taken to complete neonate to imago development, preovipositional period, and fecundity were assessed for each crop. Of all the different phenological stages of the plants investigated, A. l. lutescens could complete development to imago on vegetative flush of papaya and lime, papaya flowers, and green bean pods but on no other structures tested. There was higher survivorship to the second instar when neonates fed on green bean pods or flowers or vegetative flush of avocado, lime, or papaya crops than when neonates fed on small, medium, or large fruit of these crops. Insects that developed to the imago on green bean pods were significantly heavier than insects that developed on papaya flowers or papaya vegetative flush. The mean preoviposition period was shorter, and adult females more fecund, if they completed immature development and then fed as adults on papaya vegetative flush or green beans rather than papaya flowers. The data indicate that avocado is not a suitable host for A. l. lutescens, suggesting that adult populations that cause significant pest damage to the fruit of this crop originate elsewhere.

Life table and efficacy of Mallada desjardinsi (Chrysopidae: Neuroptera), an important predator of tea red spider mite, Oligonychus coffeae (Acari: Tetranychidae)

Green lacewing, Mallada desjardinsi Navas, is an important predator of red spider mite, Oligonychus coffeae infesting tea. Life history, life table and efficacy of M. desjardinsi were determined using red spider mite as prey under laboratory conditions. Duration of development of M. desjardinsi recorded was 5.1, 13.8 and 13 days for eggs, larvae and pupae respectively, with an average of 31.9 days from egg to adult emergence. After a mean pre oviposition period of 7.1 days, a single female laid an average of 252.6 eggs in its life time. Adult longevity of the male was recorded as 39.6 days while the females lived longer (58.2 days). The life table of M. desjardinsi was characterized by an intrinsic rate of increase (r) of 0.096 day, net reproductive rate (R 0 ) of 153.19 eggs/female, gross reproduction rate (∑mx) of 167.28 eggs/female, generation time (T) of 52.47 days, doubling time of 7.22 days and finite rate of increase(λ) of 1.1 day. The optimum predator-prey ratios were 1:50 and 1:33 under laboratory conditions however, 1:33 and 1:25 ratios were effective in green house conditions. The results of the study can be considered as a first step towards the utilization of this predator in an IPM program for the management of red spider mite infesting tea.

Reproductive Traits of <I>Glenea cantor</I> (Coleoptera: Cerambycidae: Lamiinae)

Glenea cantor (F.) is a cerambycid species that attacks living trees of at least seven plant families in Asia, and has the potential to become an invasive pest. Here we investigated its reproductive biology in the laboratory to provide vital information for the development of pest control measures and preparation of pest risk analysis. Both sexes required a period of maturation feeding before mating, with the mean premating period of males (5.87 +/- 1.68 d) being significantly longer than that of females (4.59 +/- 2.34 d). This was a synovigenic species with the mean preoviposition and oviposition period being 13.50 +/- 3.15 d and 49.46 +/- 16.16 d, respectively. If no food was available after emergence, adult males died before reaching sexual maturation and females vanished before oviposition. Paired couples mated an average of 15.12 +/- 7.02 times; 28- to 53-d-old beetles mated significantly more frequently than younger and older ones. The mean fecundity was 133.24 +/- 9.67 eggs. The oviposition rate significantly increased in the first 5 wk of the oviposition period, peaking when females were 40- to 54-d-old, and then significantly decreased in the following weeks. Reproductive activities occurred almost exclusively during the day, with most ovipositions taking place in the morning and matings in the afternoon with some overlaps.

Developmental Biology of the Tiger Moth, Atteva sciodoxa Meyrick (Lepidoptera: Yponomeutidae) under Laboratory Conditions

The tiger moth, Atteva sciodoxa is a serious pest of tongkat Ali, Eurycoma longifolia. The morphology, development times and fecundity aspects were studied at 27±2°C, 90±5% relative humidity and 12 h photoperiod. The eggs were yellow and ovoid in shape with a mean length and width of 1.19±0.02 and 0.86±0.02 mm, respectively. Width measurements of larval head capsules showed that A. sciodoxa undergoes five larval instar stages. The mean head capsule widths of the first to fifth instar larvae were 0.55±0.01, 0.89±0.01, 1.23±0.02, 1.52±0.01 and 2.11±0.02 mm, while the body lengths were 4.71±0.1, 8.63±0.1, 12.87±0.1, 16.29±0.1 and 21.74±0.2 mm, respectively. The mean male and female pupal body lengths were 10.36±0.1 and 11.26±0.2 mm, respectively. The mean male and female wing span were 21.63±0.2 and 24.28±0.2 mm, respectively. The mean pre-oviposition and oviposition periods were 6.2±0.23 and 8.5±0.28 days, respectively. A single female laid on average 106.1±4.85 eggs with maximum production between days 8-15 of adult emergence. The maximum number of eggs laid per female per day was 20.1±0.5. The mean hatching time was 5.7±0.1 days with a mean hatchability of 81.1±0.6%. The mean larval, pupal and adult periods were 20.7±0.2, 6.2±0.8 and 13.2±0.5 days, respectively. The female pupal period and adult lifespan were significantly longer than the male. Atteva sciodoxa completed its life cycle in 46.28±0.49 days.

Development of Immature Stages and Comparative Demography of Two Cucurbit-Attacking Fruit Flies in Reunion Island:Bactrocera cucurbitaeandDacus ciliatus(Diptera Tephritidae)

On Reunion Island, two species of Dacini, Bactrocera cucurbitae (Coquillett) and Dacus ciliatus Loew, infest 16 host plant species belonging to the family Cucurbitaceae from sea level to 1,600 m. These two species represent two primary pests of this plant family on the island. Melon fly, Bactrocera cucurbitae, and Ethiopian fruit fly, D. ciliatus, larval development was studied at four different constant temperatures (15, 20, 25, and 30°C) with three host plants (cucumber, pumpkin, and squash). Adult life histories of these two species were studied at 25°C with the three host plants. The results led to the conclusion that B. cucurbitae had a faster egg incubation time. Its preimaginal instars developed significantly faster than those of D. ciliatus independent of temperature. B. cucurbitae and D. ciliatus had similar mean preoviposition duration and egg hatching success. Fecundity was significantly higher for the melon fly on cucumber and pumpkin and lower on squash. Two distinctly different life- history patterns were evident: (1) later onset of reproduction, longer oviposition time, longer life span, and higher fecundity (B. cucurbitae) and (2) early reproduction, lower oviposition time, shorter life span, and lower fecundity (D. ciliatus). These results are useful for improving laboratory-rearing methods and for building simulation models to predict Dacini population dynamics.

Development of Immature Stages and Comparative Demography of Two Cucurbit-Attacking Fruit Flies in Reunion Island: <I>Bactrocera cucurbitae</I> and <I>Dacus ciliatus</I> (Diptera Tephritidae)

On Reunion Island, two species of Dacini, Bactrocera cucurbitae (Coquillett) and Dacus ciliatus Loew, infest 16 host plant species belonging to the family Cucurbitaceae from sea level to 1,600 m. These two species represent two primary pests of this plant family on the island. Melon fly, Bactrocera cucurbitae, and Ethiopian fruit fly, D. ciliatus, larval development was studied at four different constant temperatures (15, 20, 25, and 30 degrees C) with three host plants (cucumber, pumpkin, and squash). Adult life histories of these two species were studied at 25 degrees C with the three host plants. The results led to the conclusion that B. cucurbitae had a faster egg incubation time. Its preimaginal instars developed significantly faster than those of D. ciliatus independent of temperature. B. cucurbitae and D. ciliatus had similar mean preoviposition duration and egg hatching success. Fecundity was significantly higher for the melon fly on cucumber and pumpkin and lower on squash. Two distinctly different life- history patterns were evident: (1) later onset of reproduction, longer oviposition time, longer life span, and higher fecundity (B. cucurbitae) and (2) early reproduction, lower oviposition time, shorter life span, and lower fecundity (D. ciliatus). These results are useful for improving laboratory-rearing methods and for building simulation models to predict Dacini population dynamics.

Laboratory studies of the biology of Helopeltis schoutedeni Reuter (Hemiptera: Miridae), a major sucking pest of cashew (Anacardium occidentale Linn.)

Cashew (Anacardium occidentale Linn.) has become a very important non-traditional tree crop in Ghana. Several insect pests, however, have been recorded on cashew and prominent among which is the cashew mosquito, Helopeltis schoutedeni Reuter (Hemiptera: Miridae). The biology of H. schoutedeni was studied in the laboratory at 24.9 to 33oC and 72.4 to 88.5% Relative humidity (R.H.). Females pre-dominated males in the ratio of 0.7:0.3. The mean pre-oviposition, oviposition and post-oviposition periods were 3.6 ± 0.1, 10.2 ± 0.6 and 6.6 ± 0.4 days, respectively. The life cycle from egg to adult emergence lasted 24.0 days. There were five nymphal stages and the mean durations ranged from 2.7 ± 0.10 days for the 3rd instar to 3.5 ± 0.10 days for the 4th instar. The incubation averaged 8.2 ± 0.05 days. The mean pre-copulation period was 2.6 ± 0.1 days. Peak copulation activity occurred between 1400 H and 1700 H. Copulation did not take place until both sexes were at least 2 days old. Males older than three days also did not mate, no matter the age of their companion. Key words: Biology, Helopeltis schoutedeni, cashew, Ghana.

Biological aspects of Amblyomma brasiliense (Acari: Ixodidae) under laboratory conditions

Although Amblyomma brasiliense Aragão 1908 has been reported as one of the most aggressive ticks to humans in Brazil, information about the biology of this tick species is virtually inexistent. This work reports data on the life cycle of A. brasiliense fed on rabbits and pigs and maintained in an incubator at 20 degrees C, 90% RH and 12 h of light for off-host development. Tick yield of adult females fed on pigs and rabbits was 81.2% and 58.3%, respectively. Females fed on pigs had mean engorgement weight of 862.3 mg and egg mass of 208 mg, while females fed on rabbits had mean engorgement weight of 606.1 mg and egg mass of 160 mg; these values did not differ statistically between host species. Feeding period of female ticks fed on pigs (10 days) was significantly shorter than that on rabbits (17 days). Mean preoviposition period was slightly longer (35.9 days) for ticks fed on pigs than on rabbits (30 days). The minimum incubation period of eggs of ticks from both host species was similar and over 100 days. Egg production efficiency was low for females fed on both hosts (less than 30% and 20% for ticks from pigs and rabbits, respectively). More than 55% of larvae and 79% of nymphs fed on rabbits, set free inside the feeding chambers, engorged successfully. These ticks attained an engorgement weight of 1.3 and 18.2 mg, respectively, and fed for approximately 5 days. The minimum pre-molt period was 30 days for engorged larvae and over 44 days for nymphs. Molting success was low, less than 50% in the case of larvae and less than 20% for nymphs. Further studies are required to better determine the off-host requirements of this tick species.

Bionomics of the acarophagous ladybird beetle Stethorus tridens fed Tetranychus evansi

Abstract:The bionomics of Stethorus tridens Gordon fed Tetranychus evansi Baker & Pritchard were studied in the laboratory. The number of prey consumed by S. tridens increased with increasing instar levels and the total mean number consumed during immature development was 184.1 ± 18.02 T. evansi nymphs per individual. For adult male and adult female, the daily consumption was 41.3 ± 0.80 and 67.8 ± 1.69 nymphs, respectively. Stethorus tridens successfully developed to adulthood between 20 and 30°C but failed at 10, 15 and 35°C. The lower thermal threshold for egg‐to‐adult development estimated via linear regression and the modified Logan model was 9.2 and 8.1°C, respectively. The optimum and maximum temperatures for egg‐to‐adult development were around 29–31 and 32.9°C, respectively. Egg to adult development time was 23.8 ± 0.24, 17.4 ± 0.22, 16.2 ± 0.22 and 12.1 ± 0.16 days at 20, 24, 27 and 30°C, respectively. At 27°C, the sex ratio, expressed as the proportion of females, was 0.54 and the mean preoviposition, oviposition and postoviposition periods were 10.3 ± 0.67, 31.2 ± 4.74 and 30.2 ± 5.24 days, respectively. The oviposition rate was 4.0 ± 0.16 eggs/female/day with a female mean longevity of 71.6 ± 6.19 days and an intrinsic rate of natural increase of 0.104. The potential of S. tridens as a candidate natural enemy of T. evansi is discussed.

Mating success of two geographically distinct populations of Gulf Coast ticks, Amblyomma maculatum Koch

Gulf Coast ticks collected from Refugio Co., TX and Osage Co., KS are reproductively compatible despite differences in genetic haplotypes, geographic separation and seasonal phenologies. Two heifers per mating combination (TX males × TX females, KS males × KS females, TX males × KS females, KS males × TX females) were each infested with 360 pairs of Gulf Coast ticks. Only mean pre-oviposition and mean egg conversion efficiency index for the Texas male–Kansas female mating were significantly different ( p < 0.05) from other mating treatments. These females began oviposition 1-day later and used 4% less body mass toward egg production when compared to site-specific matings. However, the overall trend in reproductive performance of reciprocal tick matings was slightly lower than that of site-specific matings. There appear to be no pre-zygotic barriers to mating among Gulf Coast ticks from these Texas and Kansas populations.