Satiation time and appetite revival of Coccinella septempunctata L. (Col., Coccinellidae), a predator of Lipaphis erysimi Kalt. (Hom., Aphididae)

After a 24 h period of starvation the Coccinella septempunctata grub satiated in 85 min after eating 31.57 ± 7.12 prey (aphids). After 6, 12, 18, 24, 30 and 36 h of prey deprivation, the grub consumed 14.31 ± 5.67, 22.05 ± 5.39, 27.10 ± 6.49, 31.57 + 7.12, 33.76 + 6.52, and 36.98 ± 8.56 prey, respectively. The voluntary intake (appetite) shows a sigmoid relationship with the time since the last meal, with an upper limit of 44.30 prey irrespective of the prey deprivation period. As maximum appetite was attained after 24–36 h of deprivation, it is recommended that C. septempunctata grubs should be starved for 24 h prior to release in the biological control programme of Lipaphis erysimi.     

Oviposition strategies ofCoccinella septempunctata (Col.: Coccinellidae)

In central Japan, females ofCoccinella septempunctata brucki laid eggs preferably on the under side of metal cans, wood and other materials, and the walls of a concrete gutter in sunny grasslands with colonies of aphids, in winter and spring. These materials have a high thermal conductivity, and are warmed readily by solar radiation. The development of eggs attached to these materials was accelerated by the heart from the materials. Most eggs attached to the upper surface of such materials did not hatch because they were either desiccated by direct solar radiation or eaten by predators. The under surface of metals is heated on sunny days by solar radiation, and the eggs are protected from desiccation and cannibalism. The shortening of incubation may be an adaptation to the rapid growth of aphid populations in early spring, and may reduce the chance of cannibalism.     

Factors determining winter survival inCoccinella septempunctata (Col.: Coccinellidae)

In 1993–1995, adultCoccinella septempunctata L. were sampled at several hibernation sites in the western Czech Republic. The beetles were sexed, assorted into three body size classes and exposed in artificial hibernacula to outdoor conditions, from November to April. Average survival rate was 48.4%. Winter survival was not significantly affected by year, gender or body size. However, there were significant differences between adults from different populations (hibernation sites).     

Phenology ofCoccinella septempunctata (Col.: Coccinellidae) in central Greece

Coccinella septempunctata (Coleoptera: Coccinellidae), field collected from central Greece and reared in cages during 1990–1991 and in vials during 1994–1995 outdoors at Kifissia, Athens, developed 4 complete and a 5^th partial generations per year. In both cases, only adults of the 1st generation reproduced within the year they emerged; 2^nd, 3^rd and 4^th generation adults reproduced partly in the year they emerged and partly in the following year; 5^th generation adults did not reproduce at all in 1990, and eggs/larvae produced by 4^th generation females in 1994 died before developing into adults. Adults of the 1 st and 5th generations died before winter; those of the 2^nd, 3^rd and 4^th generations overwintered successfully. The greatest numbers of eggs were laid by females of the 1^st and 2^nd generations. Visual counts made in the open field at Kopais plain in central Greece (1990–1992) and on the summit of the adjacent Mount Kitheron (1990–1994) indicate that allC. septempunctata instars were abundant in the plain between April and June, becoming scarce from July until the end of the warm period of the year following spring. NoC. septempunctata individuals were found in the plain in winter. On the summit of the mountain,C. septempunctata adults were present all year round, singly and in aggregations, except for the month of May. The most numerous arrivals of adults were noticed on the mountain in June. Emigrations of adults from there were noticed from March until the end of April.     

Life histories ofCoccinella septempunctata brucki, propylea japonica andScymnus hoffmanni (Col., Coccinellidae) in Japan

There are seven species of coccinellids known predators of aphids infesting on field crops in Japan. In Fukuoka Prefecture, three of them,Coccinella septempunctata brucki, Propylea japonica andScymnus hoffmanni are known to occur, appearing from spring to autumn. Present study was carried out in the field to clarify the life histories of tree species of aphidophagous coccinellids.     

An artificial diet for continuous maintenance of Coccinella septempunctata adults (Coleoptera: Coccinellidae)

An artificial diet was developed for continuous maintenance of ladybird beetle (Coccinella septempunctata) adults. This beetle is an important biocontrol agent for greenhouse crops. Several biological parameters were measured and compared between colonies fed the artificial diet over eight successive generations, and colonies fed aphids. Weight, survival rates from 1st to 4th instar, pupation rate, and emergence rate were similar for both colonies, but the sex ratio (♀:♂) of the artificial diet-fed colony was higher than that of the aphid-fed colony. These results suggest that this artificial diet could meet the basic needs for the successive rearing of C. septempunctata adults. The prepared diet, which is semi-solid, provides suitable moisture for C. septempunctata, and the diet ingredients are inexpensive and relatively easy to prepare. This diet and rearing technique offers a very useful approach for mass production of C. septempunctata.     

Gut contents in field sampled adults ofCoccinella septempunctata (Col.: Coccinellidae)

During two years adultCoccinella septempunctata L. were sampled at two localities in cereals and at another location throughout the whole year in different habitats. Frequency of different food types was recorded using gut dissection. Food remains were classified into aphids, other arthropods, fungal spores, pollen, soil particles. Soil particles were relatively frequent only in early spring and pollen in late summer, whereas fungal spores were most frequent in both these periods. During ladybird reproduction in winter wheat, aphid remains were present in 76.9–91.7% of all individuals and surprisingly spores were again more frequent than remains of other arthropods. Cannibalism was rare. Food ofC. septempunctata was very uniform, because nearly always the same spores (Alternaria sp.) and other arthropods (Thysanoptera) were found. Additionally a semiquantitative analysis was performed with a simple scale of gut fullness. Only in certain cases significant positive correlation were determined between aphid density in the field and the calculated “feeding state” as well as frequency of aphid remains.     

Possible storage of Coccinella undecimpunctata (Col., Coccinellidae) under low temperature and its effect on some biological characteristics

Developmental stages of Coccinella undecimpunctata L. were stored at 6.0°C for various storage periods in a refrigerator. Egg hatching was 65.0% after 7 days of storage. However, no egg hatching were observed after 15, 30, 45 and 60 days of storage. The survival of the third and fourth instar larvae was higher than the first and second instar. The survival of larvae declined sharply after 15 days. No larvae survived after 30 or 60 days of storage. Emergence percentage of adults from stored pupae varied from 85.0 to 25.0% after storage for 7 up to 30 days. The survival percentage of adults differed and appeared to depend on prior feeding before storage. From the present results, it appears that the adult stage may be better able to survive extended periods of storage than the other developmental stages. In addition, it was found that prior feeding of adult stage affected the longevity, fecundity and consumption rate.     

Prey-predator relationship between Lipaphis erysimi Kalt. (Hom., Aphididae) and Coccinella septempunctata L. (Col., Coccinellidae). II. Effect of host plants on the functional response of the predator

The present paper examines the effect of the host plants Brassica oleracea, Raphanus sativus and Brassica campestris on which Lipaphis erysimi was reared, on the functional response of the grub of Coccinella septempunctata . The functional response of the grub of C. septempunctata is of type II. The amount of prey consumption increases significantly with the increase of prey density and is maximum in B. oleracea- reared aphids, followed by those reared on R. sativus and B. campestris . The percentage prey consumption declined throughout. This decrease was a maximum for aphids reared on B. campestris followed by R. sativus - and B. oleracea -reared aphids. Analysis of variance also confirmed that the number and percentage prey consumption was significantly influenced between the three host plants and between 12 prey densities. Results show that C. septempunctata has a greater liking for aphids reared on B. oleracea rather than those reared on the other plants that were tested.     

Summer diapause and winter quiescence ofCoccinella septempunctata (Col. Coccinellidae) in central Greece

Coccinella septempunctata (Coleoptera: Coccinellidae) in Greece is a multivoltine species. In the lowlands, all instars are abundant in spring becoming scarce from July until the end of the warm period of the year; they are absent in winter. In June, mostC. septempunctata adults migrate to mountainous aestivo-hibernation sites. Measurements of the duration of pre-oviposition period in females taken monthly from the summit of Mount Kitheron in central Greece (1993–1994) and transferred to laboratory conditions of high temperature (25°C), long day (16 hrs light/24 hrs), and presence of aphids, indicated that theC. septempunctata females were in diapause during July and August. The diapause gradually terminated from late August to late October and was followed by a period of quiescence extending from November to March of the following year. During the summer diapause, arrest of ovarian development was indicated by immaturity of the ovaries in all sampled females and the complete absence of vitellogenic resorption signs. Also, adults were found with enlarged fat bodies, and the median duration of preoviposition period in females transferred to the above laboratory conditions was 90 days in early July and 82 days in early August. During the period of winter quiescence, arrest of ovarian development was characterized in most samples by immaturity of the ovaries in all females and, in some samples, by the presence of a few females with signs of vitellogenic resorption. In winter, adults were found containing fat body reserves of different levels, and the median preoviposition period of females transferred to optimal breeding conditions was 29 days in early November and 16 days in mid January.     

Complete mitochondrial genome of the seven-spotted lady beetle, Coccinella septempunctata (Coleoptera: Coccinellidae)

The complete mitochondrial genome (mitogenome) of the seven-spotted lady beetle, Coccinella septempunctata (Coleoptera: Coccinellidae), which is one of the best known insects capable of predation, is described with an emphasis on the noteworthy composition of the A+T-rich region. The C. septempunctata genome consists of 2 rRNAs, 22 tRNAs, 13 protein-coding genes, and 1 control region, designated as the A+T-rich region in insects. Along with an unusually long A+T-rich region (4469 bp), the 18,965-bp long C. septempunctata mitogenome was the largest in Coleoptera. The A+T-rich region is composed of a 2214-bp long non-repeat region composed of 80.17% A/T nucleotides and a 2256-bp long repeat region composed of 65.71% A/T nucleotides. The repeat region harbors 32 identical 70-bp long tandem repeats plus one 15-bp long incomplete first repeat. These repeat sequences may possibly have been caused by slipped-strand mispairing and unequal crossing-over events during DNA replication.     

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

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.     

Numerical response of ladybird beetles (Col., Coccinellidae) to aphid prey (Hom., Aphididae) in a field bean in north-east India

Two predaceous species of Coccinellidae, Menochilus sexmaculatus and Coccinella transversalis , occurred abundantly in bean crops infested with the aphid, Aphis craccivora Koch in north-east India. The number of eggs and adults of the two coccinellids increased in response to the increase in the population of aphid prey. Reproductive numerical responses were found to be synchronous to prey density whereas aggregative numerical responses appeared asynchronous in the later part of the aphid cycle on beans. Menochilus sexmaculatus oviposited smaller clusters of eggs at lower density of aphids than C. transversalis which laid larger clusters and showed greater numerical response at higher densities of aphids. Within a species cluster the size of the eggs seems to be directly related to aphid density. The two coccinellid species of this study seem to be efficient predators of A. craccivora in terms of their reproductive and aggregative numerical responses.     

Locomotory behavior of flightless Harmonia axyridis Pallas (Col., Coccinellidae)

To improve the efficiency of the ladybeetle Harmonia axyridis as a biological control agent against aphids, a flightless population was produced by feeding adults with a mutagen and selecting their progeny for non-flying but otherwise morphologically normal individuals. The inability to fly could result from a change in their flying behavior compared with control adults. Flight duration was very much shorter, wing beat frequency and more particularly the amplitude of the wing beats were clearly lower. More time was spent on the other components of flight behavior such as wing rotation, wing immobility and wing folding. The sequence of these patterns differed slightly mainly due to changes in their frequency. The locomotory behavior was not modified by the mutation, which only affected the wing muscles. The searching behavior of mutant adults differed from that of control adults only in that they took longer to encounter and ingest aphids. As this difference is not important, it should be possible to use this flightless population in biological control programs.     

Functional and numerical responses of Propylea dissecta (Col., Coccinellidae)

The functional response of a ladybeetle, Propylea dissecta, to increasing density of aphid, Aphis gossypii, was of the curvilinear shape depicting Holling's type II response with fourth instar larva being the most voracious stage when compared with adult male and female. Prey handling time by different predatory stages decreased from 65.45 to 8.72 min with increase in prey density from 25 to 800. The predator aggregation and high prey density reduces the searching efficiency of the predator. Area of discovery was highest (1.4437) when a single predator was searching at minimum aphid density (25) and lowest (0.0366) when eight predators were searching at a constant aphid density (200). Mutual interference and quest constants were 0.75 and 0.40, respectively. The reproductive numerical response, in terms of eggs laid, increased curvilinearly with prey density and female laid 70.5 ± 5.55 eggs when exposed to highest prey density (400) and 12.3 ± 0.79 eggs at lowest prey density (10). The similar shapes of both functional and reproductive responses indicate that both responses are interlinked and function simultaneously.     

Locomotor Behavior of Flightless Harmonia axyridis Pallas (Col., Coccinellidae)

To improve the efficiency of the lady beetle H. axyridis as a biological control agent against aphids, a flightless population was obtained by feeding adults with a mutagen and selecting their progeny for nonflying but otherwise morphologically normal individuals. These flightless adults attempted to fly but immediately fell. They softened their fall by opening their elytrae and wings. The inability to fly could result from change in their flying behavior compared to control adults. The flight duration was very much shorter, and the wing beat frequency and, more particularly, the amplitude of the wing beats were clearly lower. More time was spent in the other components of the flight behavior such as wing rotation, wing immobility, and wing folding. The sequence of these patterns differed slightly, due mainly to change in their frequency. The locomotor behavior was not modified by the mutation, which affected only the wing muscles. Searching behavior of mutant adults differed from that of control adults only in that they took longer to encounter and ingest aphids. Nevertheless, the larval growth and reproductive rate remained unchanged. The behavioral and biological features of these flightless adults indicate that it should be possible to use them in biological control programs.     

Host finding byCryptolaemus montrouzieri (Col., Coccinellidae) a predator of mealybusgs (Hom., Pseudococcidae)

AdultC. montrouzieri were able to detect their prey by visual and chemical stimuli. Presence of mealybug caused a significant increase in the number of turns and a sharp decrease in flight attempts suggesting detection by olfaction. In the light, adult predators found polystyrene dummies significantly faster than under dark (red light) conditions, but light had no effect on the time taken for adults to pass across an invisible test point. Fourth instar larvae could only perceive the prey by physical contact.      

Ecological requirements for hibernatingPropylea quatuordecimpunctata (L.) andCoccinella septempunctata [Col.: Coccinellidae]

During 3 successive winters, we studied the dormancy sites ofPropylea quatuordecimpunctata (L.) andCoccinella septempunctata L., 2 species of ladybirds which hibernate in leaf litter. Samples of litter were taken from several kinds of forest to study the influence of 3 variables (exposure; altitude; sampling place: edge or inner wood) on the abundance of ladybirds. We found the ecological requirements of the 2 species of coccinellids to be quite different:C. septempunctata prefers forest edges orientated towards the South and the West.P. quatuordecimpunctata prefers the inner wood and does not show a preference for station exposure. For each species, the number of ladybirds collected in the samples is positively correlated with station altitude. In addition, some observations were carried out to examine the main mortality factors just before and during dormancy. In maize fields near dormancy sites, the harvest is very harmful forC. septempunctata. During the winter,P. quatuordecimpunctata andC. septempunctata suffer fromBeauveria ssp. and some ladybirds have parasitoïds.     

Trophic regulation of postdiapause ovariole maturation inCoccinella septempunctata [Col.: Coccinellidae]

In 1977 the vernal maturation ofCoccinella septempunctata L. females was investigated in relation to the variation in aphid population density on alfalfa and cereals in central Bohemia. The ovarioles do not ripen unless the aphid population density reaches a certain threshold. This leads to considerable variability in the time of vernal reproductive activity (up to 1.5 months in the same geographic locality) among subpopulations living on crops with different aphid densities. This mechanism enables the reproduction of the aphidophagous insect to synchronize with the population development of the aphid.