Biogenic amines in protocerebral A2 neurosecretory neurons of Lymantria dispar L. (Lepidoptera:Lymantriidae): Response to trophic stress

The number, morphometric parameters and amount of aminergic neurosecretory product of protocerebral A2 neurosecretory neurons were investigated in the fifth instar of Lymantria dispar caterpillars, following a suitable or unsuitable trophic regime. Caterpillars originated from two populations (Quercus rubra or Robinia pseudoacacia forest) and were differently adapted to trophic stress, i.e. feeding on locust tree leaves - unsuitable host plant. The number of neurosecretory neurons was higher in the caterpillars originated from Robinia population than in Quercus population, regardless of feeding. A2 neurosecretory neurons, nuclei and their nucleoli were larger in caterpillars fed with unsuitable leaves in both populations. There was more aminergic product in the A2 neurosecretory neurons of the caterpillars fed with unsuitable leaves independently of population origin

The 2-Domination Number of a Caterpillar

A set D of vertices in a graph G is a 2-dominating set of G if every vertex in V − D has at least two neighbors in D. The 2-domination number of a graph G, denoted by γ2(G), is the minimum cardinality of a 2- dominating set of G. In this thesis, we discuss the 2-domination number of a special family of trees, called caterpillars. A caterpillar is a graph denoted by Pk(x1, x2, ..., xk), where xi is the number of leaves attached to the ith vertex of the path Pk. First, we present the 2-domination number of some classes of caterpillars. Second, we consider several types of complete caterpillars. Finally, we consider classification of caterpillars with respect to their spine length and 2-domination number

Eco control of agro pests using imaging, modelling & natural predators

Caterpillars in their various forms: size, shape, and colour cause significant harm to crops and humans. This paper offers a solution for the detection and control of caterpillars through the use of a sustainable pest control system that does not require the application of chemical pesticides, which damage human health and destroy the naturally beneficial insects within the environment. The proposed system is capable of controlling 80% of the population of caterpillars in less than 65 days by deploying a controlled number of larval parasitoid wasps (Cotesia Flavipes, Cameron) into the crop environment. This is made possible by using a continuous time model of the interaction between the caterpillar and the Cotesia Flavipes (Cameron) wasps using a set of simultaneous, non-linear, ordinary differential equations incorporating natural death rates based on the Weibull probability distribution function. A negative binomial distribution is used to model the efficiency and the probability that the wasp will find and parasitize a host larva. The caterpillar is presented in all its life-cycle stages of: egg, larva, pupa and adult and the Cotesia Flavipes (Cameron) wasp is present as an adult larval parasitoid. Biological control modelling is used to estimate the quantity of the Cotesia Flavipes (Cameron) wasps that should be introduced into the caterpillar infested environment to suppress its population density to an economically acceptable level within a prescribed number of days. Keywords

Sequential sampling for panicle caterpillars (Lepidoptera: Noctuidae) in sorghum

Citation: Elliott, N. C., M. J. Brewer, K. L. Giles, G. F. Backoulou, B. P. McCornack, B. B. Pendleton, and T. A. Royer. 2014. “Sequential Sampling for Panicle Caterpillars (Lepidoptera: Noctuidae) in Sorghum.” Journal of Economic Entomology 107 (2): 846–53. https://doi.org/10.1603/EC13413.Panicle caterpillars comprise an economically important insect pest complex of sorghum throughout the Great Plains of the United States, particularly in Kansas, Oklahoma, and Texas. The sorghum panicle caterpillar complex consists of larvae of two polyphagous lepidopteran species: the corn earworm, Helicoverpa zea (Boddie), and fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Sampling for panicle caterpillars in sorghum fields is usually accomplished by the beat bucket sampling technique with a fixed sample size of 30 beat bucket samples of one sorghum panicle each per 16.2 ha of field. We used Wald's sequential probability ratio test for a negative binomial distribution to develop a sequential sampling plan for panicle caterpillars. In total, 115 sorghum fields were sampled in Kansas, Oklahoma, and Texas from June to August 2010. Panicle caterpillars had an aggregated distribution of counts confirmed by Pearson's chi-square statistic for lack of fit to the negative binomial distribution for each sampled field. A sequential sampling plan was developed using a high threshold (an economic threshold) of 0.5 caterpillars per sorghum panicle, a low threshold (a safe level) of 0.20 caterpillars per panicle, and fixed error rates (α = 0.10 and β = 0.05). At caterpillar densities >0.45 and <0.12 per panicle, the average number of panicles inspected to make a decision was less than the current recommendation of 30. In a 2013 validation test of 25 fields, the expected number of samples taken from average sample number curve was in close agreement with the number of samples required using the sequential plan (r 2 = 0.93), and all fields were correctly classified when compared with a fixed sample size result. The plan improved upon current sampling recommendations for panicle caterpillars in sorghum because at known acceptable fixed error rates fewer samples were required when caterpillars are scarce or abundant, whereas more samples were required to make decisions with the same acceptable error rates when densities were near the economic thresholds

Biogenic amines in protocerebral A2 neurosecretory neurons of Lymantria dispar L. (Lepidoptera:Lymantriidae): Response to trophic stress

The number, morphometric parameters and amount of aminergic neurosecretory product of protocerebral A2 neurosecretory neurons were investigated in the fifth instar of Lymantria dispar caterpillars, following a suitable or unsuitable trophic regime. Caterpillars originated from two populations (Quercus rubra or Robinia pseudoacacia forest) and were differently adapted to trophic stress, i.e. feeding on locust tree leaves - unsuitable host plant. The number of neurosecretory neurons was higher in the caterpillars originated from Robinia population than in Quercus population, regardless of feeding. A2 neurosecretory neurons, nuclei and their nucleoli were larger in caterpillars fed with unsuitable leaves in both populations. There was more aminergic product in the A2 neurosecretory neurons of the caterpillars fed with unsuitable leaves independently of population origin.Projekat ministarstva br. 17302

Long-term effects of clear-cut forestry on predation of artificial caterpillars in boreal forests of southeastern Norway

Predator-prey interactions are one of the key ecological interactions contributing to ecosystem structure and stability within complex forest ecosystems. Intact forest ecosystems contain high abundances and diversity of prey and natural enemies, but impact from forest management intensities could potentially threaten these interactions. I used 640 artificial caterpillars made from brown or green plasticine to compare predation rates between 10 pairs of boreal near-natural (NN) forests and former clear-cut (CC) forests in the southeastern parts of Norway. Half of them were placed on tree stems, and the other half on bilberry bushes. Artificial caterpillars were placed out in two periods, from late May to late June 2022. Predation was measured in two ways: by recording the presence or absence of attack marks on caterpillars, which could indicate predation rates by arthropods, mammals, or birds; and by counting the number of arthropod attack marks per caterpillar. I also assessed the abundance of predatory beetles in traps and the occurrence of anthills in late June. 108 caterpillars were fully removed by unknown predators. From the remaining caterpillars, were 88% attacked by arthropods, 46% by mammals, and 14% by birds. Almost twice as many caterpillars were removed from the former clear-cut forests as near-natural forests (21% vs. 13%), especially on bilberry bushes, and during the second period. Forest type was a significant predictor of both presence of arthropod predation, and number of arthropod attack marks per caterpillar. The arthropod predation rates of caterpillars were highest in the near-natural forests, especially the first period, but caterpillars in clear-cut forests suffered more attack marks per caterpillar, specifically brown ones. Arthropod predators significantly preferred caterpillars on tree stems, particularly the first period. The colour preference of arthropods was only pronounced the second period, with significantly less predated green caterpillars. Both anthills and predatory beetles significantly increased arthropod attack marks per caterpillar. Bird and mammal predation did not differ significantly between the two forest types, they only showed a preference for caterpillars placed on bilberry bushes. My results indicate that different predators react differently to forest management regimes, caterpillar colour, and placement, highlighting the importance of further investigations towards impacts from forest type and other potential ecological interactions on predation rates