Daily Prey Consumption Research Articles

Prey consumption by larval and adult stages of the entomophagous ladybird Serangium parcesetosum Sicard (Col., Coccinellidae) of the cotton whitefly, Bemisia tabaci (Genn.) (Hom., Aleyrodidae), at two different temperatures

The entomophagous ladybird, Serangium parcesetosum Sicard (Col., Coccinellidae) appears to be a promising predator against the cotton whitefly, Bemisia tabaci (Genn.) (Hom., Aleyrodidae). Knowledge about its consumption of B. tabaci is incomplete. The present study was undertaken to determine the potential use of this predator in biological control programs. The daily and total prey consumption of S. parcesetosum through the entire development of the larval instars as well as during three different periods of longevity of adult females and males feeding on nymphs or puparia of B. tabaci as prey was examined. In addition, the daily prey consumption of the adult females where the number of B. tabaci puparia was altered was studied at two different temperatures in the laboratory. The results showed that the mean daily prey consumption of nymphs or puparia of B. tabaci by larval instars of S. parcesetosum increased gradually as development progressed at both temperatures. Significant differences were found in the mean total prey consumption among the different predatory larval instars. In total, S. parcesetosum consumed during its entire larval development significantly more nymphs than puparia; at 18°C it consumed a mean of 1,566.1 (♀) and 1,443.9 (♂) nymphs or 280.0 (♀) and 250.8 (♂) puparia, while at 30°C, it consumed a mean of 1,119.1 (♀) and 979.9 (♂) nymphs or 188.2 (♀) and 171.6 (♂) puparia. Over the three studied periods of the adult stage of S. parcesetosum, the mean daily prey consumption by the females and males fluctuated irregularly at both temperatures. At 18°C and 30°C, both females and males consumed significantly more nymphs than puparia. No significant differences were found between females and males with respect to consumption of nymphs, although significant differences were found between the sexes with respect to consumption of puparia, but at 18°C only. The mean total prey consumption over the three studied adult stages was 2,188.4 (♀) and 1,994 (♂) nymphs or 727.1 (♀) and 624.8 (♂) puparia at 18°C, while at 30°C the mean values were 3,947.7 (♀) and 3,577.3 (♂) nymphs or 1,600.5 (♀) and 1,448.8 (♂) puparia. S. parcesetosum adapted smoothly to fluctuating prey availability, where the mean daily prey consumption became higher when 50 puparia/day was offered. In contrast, the predator consumed most individuals when the number of prey supplied was 10 or 5 puparia/day. Prey consumption decreased during the second experimental week in the trial, before which 50 puparia/day had been offered. In the other trials, before which 20, 10 and 5 puparia/day had been offered, a considerable increase in prey consumption was noted.

Prey quality dependent growth, development and reproduction of a biocontrol agent, Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae)

Growth, development and reproduction of a ladybird beetle, Cheilomenes sexmaculata (Fabricius) were investigated in relation to seven aphid species, viz. Aphis craccivora Koch, Aphis gossypii Glover, Rhopalosiphum maidis (Fitch), Myzus persicae (Sulzer), Uroleucon compositae (Theobald), Lipaphis erysimi (Kaltenbach) and Aphis nerii Boyer de Fonscolombe on specific hosts. Maximum prey consumption, percent larval survival, developmental rate, weight of different life stages, percent adult emergence, adult longevity and fecundity of C. sexmaculata were recorded on A. craccivora, and minimum on A. nerii. A linear relationship was found between development rate and weight of adult, daily prey consumption and relative growth rate, log weights of adult males and females, and female longevity and total fecundity. On the basis of overall performance of ladybird the order of suitability of prey species was A. craccivora>A. gossypii>R. maidis>M. persicae>U. compositae>L. erysimi>A. nerii.

Prey consumption preferences of Serangium parcesetosum Sicard (Col., Coccinelidae) for different prey stages, species and parasitized prey

Serangium parcesetosum Sicard (Col., Coccinellidae) is considered one of the important predators of whiteflies. However, knowledge about its preferences for different prey stages, species and parasitized prey is still lacking in the literature. The present work investigated the preferences of S. parcesetosum for different stages of B. tabaci, different prey species and B. tabaci parasitized by Encarsia formosa Gahan (Hym., Aphelinidae) by prey consumption at different temperatures in the laboratory. Results showed that L2 and L4 predatory instars of S. parcesetosum preferred puparia to nymphs and eggs of Bemisia tabaci (Genn.) (Hom., Aleyrodidae). The mean daily prey consumption was 5.1–9.0, 4.5–6.2 and 3.6–4.3 by L2 and 6.4–9.7, 5.5–8.5 and 2.5–7.5 by L4 for puparia, nymphs and eggs, respectively. Adult females, however, indicated a significantly greater preference for both puparia and nymphs, consuming a daily mean of 6.4–7.5 puparia and 5.1–6.7 nymphs, but only 3.0–4.7 eggs. At 18 and 30 °C, all S. parcesetosum stages tested significantly preferred B. tabaci and Trialeurodes vaporariorum Westwood (Hom., Aleyrodidae) over the other three prey species offered. At both temperatures, all predatory stages preferred B. tabaci to T. vaporariorum, the L2 instar at 18 °C, showing significantly more preference for B. tabaci than T. vaporariorum. In contrast, very few individuals were consumed from Aphis gossypii Glover (Hom., Aphididae), Frankliniella occidentalis (Pergande) (Thys., Thripidae) and Tetranychus urticae Koch (Acari, Tetranychidae). At 18 °C, a daily mean of 7.5–8.0, 6.6–9.0 and 6.7–8.1 B. tabaci as well as 5.3–6.4, 5.4–7.8 and 5.6–6.3 T. vaporariorum was consumed by L2, L4 and adult females, respectively, while at 30 °C, L2, L4 and adult females consumed a mean of 9.3, 8.8–9.7 and 8.3–9.7 B. tabaci/day as well as 8.3–9.0, 7.8–9.1 and 5.5–8.4 T. vaporariorum/day, respectively. S. parcesetosum L2 and L4 instars as well as adult females and males at both studied temperatures showed a significant tendency to avoid B. tabaci puparia after 5 days of parasitism by E. formosa and preferred to feed on unparasitized whiteflies. At 18 °C, the mean daily consumption was 8.7 and 0.2 (L2), 11.1 and 0.6 (L4), 12.1 and 1.0 (♀♀) as well as 10.5 and 0.2 (♂♂), while at 30 °C the means were 15.9 and 0.5 (L2), 19.8 and 1.0 (L4), 18.9 and 1.2 (♀♀) as well as 17.4 and 0.6 (♂♂) from unparasitized and parasitized B. tabaci puparia, respectively.

Influence of prey species on immature survival, development, predation and reproduction of Coccinella transversalis Fabricius (Col., Coccinellidae)

Abstract:Six aphid species, viz. Aphis craccivora, Aphis gossypii, Aphis nerii, Myzus persicae, Lipaphis erysimi and Uroleucon compositae were provided as prey to the feeding stages of Coccinella transversalis (Fabricius). All of them were found to be essential prey, however the relative prey suitability varied. All the predatory stages of C. transversalis consumed and preferred A. gossypii, the most and A. nerii, the least. Significant effect of prey quality was observed on pre‐imaginal developmental periods, wet weights and adult longevity. The complete development was shortest on A. gossypii (13.01 ± 0.18 days) and longest on A. nerii (20.51 ± 0.25 days). The total prey consumption by larva, adult male and female in their lifetime was maximum (665.30 ± 5.75, 4831.10 ± 123.54 and 5412.30 ± 94.51, respectively) on A. gossypii and minimum (434.80 ± 4.03, 802.80 ± 34.37 and 905.20 ± 52.48, respectively) on A. nerii. Immature survival, growth index and adult emergence of C. transversalis was maximum (68.33, 7.82 and 88.21%, respectively) when larval instars consumed A. gossypii and minimum (37.75, 2.18 and 60.69%, respectively) after feeding on A. nerii. Female reproduction was also prey quality dependent showing maximum reproductive performance in terms of fecundity and percentage viability, with a highest reproductive period and lowest non‐reproductive period on A. gossypii, followed by A. craccivora, L. erysimi, M. persicae, U. compositae and A. nerii. Regression analysis revealed a positive correlation between: (1) daily prey consumption and relative growth rate, (2) adult weight and developmental rate, (3) weights of adult male and female, and (4) female longevity and fecundity.

Prey consumption and functional response of three acarophagous species to eggs of the two-spotted spider mite in the laboratory

Comparative investigation of the characteristics related to prey consumption, reproductive rate and searching capacity among predators, which remain largely unexplored, could yield important information for selection of novel control agents. In this paper, the daily prey consumption rate of the immature stages and adult females until 20 days after eclosion of three predators, Stethorus japonicus (lady bug), Scolothrips takahashii (predatory thrips) and Amblyseius californicus (predatory mite), on eggs of Tetranychus urticae (red form) was determined, as well as the functional response of adult females to T. urticae eggs, on lima bean leaf discs in the laboratory at three constant temperatures (18–20, 25 and 30°C) and 16L : 8D. Female and male immatures of S. japonicus consumed the same number of spider-mite eggs, whereas more eggs were eaten by female immatures of S. takahashii and A. californicus than by male immatures at each of the temperatures tested. The total number of eggs consumed during the immature stages did not differ significantly among temperatures for any of the three predators. Consumption of T. urticae eggs by S. japonicus was fastest, followed by S. takahashii. Average daily consumption rates of adult females during the first 20 days after emergence at 25°C were 13.4 eggs for A. californicus, 23.0 eggs for S. takahashii and 294.4 eggs for S. japonicus. Adult females of the three predator species showed a type II functional response to prey density, regardless of the temperatures tested.

Effects of different high constant and alternating temperatures on the development and prey consumption of Dicyphus tamaninii Wagner (Heteroptera, Miridae) with Aphis gossypii Glover (Homoptera, Aphididae) as prey

The present work aimed to study the effects of high constant and alternating temperatures on the development and prey consumption by Dicyphus tamaninii Wagner (Het., Miridae) with Aphis gossypii Glover (Hom., Aphididae) as prey.Results showed that the predator was able to successfully develop and reach the adult stage, on average, after 20.1 (♀♀) and 20.6 (♂♂) days at a temperature of 30 ± 1 °C with A. gossypii as prey. On the other hand, it was not able to develop at 35 ± 1 °C, here all N1 instars used at the beginning of the experiments had died even before moulting to N2 instar. At alternating temperatures of 25/15 ± 1 °C, the predator reached the adult stage 23.7 (♀♀) and 23.5 (♂♂) days after egg hatching, whereas when the temperatures were increased to 35/22 ± 1 °C, it took a significantly shorter period: 20.6 (♀♀) and 20.9 (♂♂) days. In general, the highest mortality occurred during the first two nymphal instars. The total percentage mortality during development from N1 to adult stage was 30 % and 100 % at the constant temperatures 30 ± 1 °C and 35 ± 1 °C, respectively. At the alternating temperatures of 25/15 ± 1 °C, it was lowest with 16.5 %, while at 35/22 ± 1 °C, it was 20 %.The results of the experiments on prey consumption showed that an individual D. tamaninii consumed during its development to adult stage at 30 ± 1 °C an average of 442.2 (♀♀), 433.6 (♂♂) aphids. At the constant temperature of 35 ± 1 °C, the average daily prey consumption started with 4 aphids and decreased continuously till it approached nil on the 9th day, where all predatory nymphs died. At the alternating temperatures of 25/15 ± 1 °C, the total prey consumption during development was, on average, 359.3 (♀♀) and 297.0 (♂♂) aphids, while at 35/22 ± 1 °C it was 348.5 (♀♀) and 334.0 (♂♂) aphids. The effect of the four temperatures on the prey consumption by D. tamaninii during the first 10 days after emergence was also studied. At a constant temperature of 30 ± 1 °C, a total of 446.4 (♀♀) and 372.0 (♂♂) aphids were consumed, compared to 40.6 (♀♀) and 39.0 (♂♂) at 35 ± 1 °C. At alternating temperatures of 25/15 ± 1 °C, the predatory adult consumed, on average, a total of 267.0 (♀♀) and 207.0 (♂♂) aphids. Increasing the temperature to 35/22 ± 1 °C resulted in a higher prey consumption by the adult predator, reaching 351.5 (♀♀) and 267.7 (♂♂) aphids over the same period.In conclusion, results indicated that D. tamaninii is a promising predator of the melon aphid at a temperature spectrum ranging from 15 ± 1 °C up to 35 ± 1 °C.

Influence of six aphid prey species on development and reproduction of a ladybird beetle, Coccinella septempunctata

Pre-imaginal development, immaturesurvival, and reproduction of a ladybird, Coccinella septempunctata Linnaeus, werestudied in response to six aphid species, Aphiscraccivora Koch, Aphis gossypii Glover,Aphis nerii Boyer de Fonscolombe,Lipaphis erysimi (Kaltenbach), Myzuspersicae (Sulzer) and Uroleuconcompositae (Theobald) to quantify theirrelative suitability as prey. Pre-adultdevelopment was shortest (13.93 ± 0.12 days)when fed on L. erysimi and longest(22.85 ± 0.10 days) on A. nerii. Immaturesurvival, adult emergence, growth index,relative growth rate, development rate, maleand female longevity, oviposition period,fecundity and hatching percent were maximal, i.e. 73.47 ± 0.89%, 90.07 ± 1.43%,8.62 ± 0.23, 1.52 ± 0.02, 0.07,81.10 ± 1.26 days, 85.70 ± 1.45 days,69.80 ± 1.32 days, 1764.10 ± 8.46,and 87.88 ± 1.05, respectively when C.septempunctata were fed on L. erysimi.The same parameters were minimal, i.e.43.86 ± 1.33%, 71.65 ± 2.75%,2.02 ± 0.08, 0.49 ± 0.02, 0.04,44.40 ± 1.39 days, 53.50 ± 1.00 days,16.40 ± 0.60 days, 203.20 ± 11.83, and48.68 ± 2.06, respectively on A. nerii. Theweights of different ladybird life stages weremaximal after feeding on L. erysimi and minimalon A. nerii. Regression analyses of thedata revealed linear relationships betweendevelopment rate and weight of adult; dailyprey consumption and relative growth rate; logweight of adult male and female; and longevityand fecundity of female. On the basis of thesefindings, the order of suitability of aphidspecies for C. septempunctata is L. erysimi >M. persicae > A. craccivora > A. gossypii >U. compositae > A. nerii. Thus, the presentinformation can be utilized for the massrearing of C. septempunctata by supplyingthe best food and can also help in theprediction of the relative abundance of theladybird on different aphid infestations in thefields.

Estimated Loss of Juvenile Salmonids to Predation by Northern Squawfish, Walleyes, and Smallmouth Bass in John Day Reservoir, Columbia River

–We estimated the loss of juvenile salmonids Oncorhynchus spp. to predation by northern squawfish Ptychocheilus oregonensis, walleyes Stizostedion vitreum, and smallmouth bass Micropterus dolomieu in John Day Reservoir during 1983–1986. Our estimates were based on measures of daily prey consumption, predator numbers, and numbers of juvenile salmonids entering the reservoir during the April–August period of migration. We estimated the mean annual loss was 2.7 million juvenile salmonids (95% confidence interval, 1.9–3.3 million). Northern squawfish were responsible for 78% of the total loss; walleyes accounted for 13% and smallmouth bass for 9%. Twenty-one percent of the loss occurred in a small area immediately below McNary Dam at the head of John Day Reservoir. We estimated that the three predator species consumed 14% (95% confidence interval, 9–19%) of all juvenile salmonids that entered the reservoir. Mortality changed by month and increased late in the migration season. Monthly mortality estimates ranged from 7% in June to 61% in August. Mortality from predation was highest for chinook salmon O. tshawytscha, which migrated in July and August. Despite uncertainties in the estimates, it is clear that predation by resident fish predators can easily account for previously unexplained mortality of out-migrating juvenile salmonids. Alteration of the Columbia River by dams and a decline in the number of salmonids could have increased the fraction of mortality caused by predation over what it was in the past.

Rates of Prey Consumption by Neotropical Robber Flies (Diptera: Asilidae)

Adult robber flies are sit-and-wait predators that attempt aerial capture of flying insects. Estimates of daily rates of prey consumption per individual were combined with estimates of absolute population densities to obtain daily, populational rates of prey consumption for nine robber fly species in a lowland neotropical forest. Estimates of biomass consumed/day/ha/population varied from 23 to 1425 mg (dry weight) among the nine species, and total daily consumption for all species was approximately 4600 mg (dry weight)/ha. This latter value was relatively low compared to estimates available for other insectivorous taxa. Although many studies have measured consumption rates of insect herbivores (Teal 1962, Van Hook 1971, Reichle et al. 1973) or detritivores (Kowal & Crossley 1971, McBrayer & Reichle 1971, Santos & Whitford 1981), few studies provide estimates of prey consumption (i.e., ingestion) rates by insect predators. I am aware of only two studies in nonagricultural ecosystems that estimate prey biomass consumed per unit area of habitat per unit time by populations of predatory insects, and both of these concern populations of nymphal stoneflies (Plecoptera) in alpine streams of western North America. Siegfried and Knight (1976) reported an annual prey consumption estimate of 3.7 g/m2 (dry mass) for Calineuria californica in a Californian stream. Allan (1982) studied three stonefly species in Colorado and estimated total annual prey consumption by all species to be 3.0 g/m2 (dry mass). Both studies suggested that predatory stoneflies consume a significant fraction of the prey biomass available. Previous reports (Shurovnekov 1962, Joern & Rudd 1982) also suggest that robber flies have a major impact upon prey populations. However, the data collected do not allow calculation of consumption rates in terms of prey biomass taken per unit area and consequently can not be directly compared with consumption rates for other predatory species. Here I present estimates of daily prey consumption rates for populations of nine robber fly species in a lowland neotropical forest. Adults of all nine species are visual, sit-and-wait predators that attempt aerial capture of flying insect prey. Following a successful capture, individuals return to a perch and consume the liquid contents of the prey. Since attack rate, proportion of sucI Received 16 October 1984, revision accepted 16 April 1985. 2 Present address: Pacific Biomedical Research Center, University of Hawaii at Manoa, Honolulu, Hawaii 96822, U.S.A. 166 BIOTROPICA 18(2): 166-17

Laboratory observations on the predation of Toxorhynchites rutilus rutilus on Aedes aegypti (Diptera: Culicidae).

Laboratory tests indicated that the predatory activity of 4th-instar Toxorhynchites rutilus rutilus larvae is affected by the size of container, prey density and prey stage. The rate of prey consumption was found to vary inversely with container size and directly with prey density; the incidence of killing behavior, where the prey is killed but not consumed, varied in a similar fashion. The predators, during the 4th instar, consumed less prey pupae than 4th instars, and more 1st- than 4th-instar larvae. While consumption rates varied considerably, pupal weights or development times of the predator could not be correlated with total or daily prey consumption.