Understanding predator-prey dynamics is pivotal for advancing sustainable pest management strategies. This study examined the functional response of Harmonia axyridis across six developmental stages when preying upon the eggs of two destructive lepidopteran pests including Spodoptera litura and Spodoptera frugiperda. Using logistic regression and Holling’s disc equation, a clear Type II functional response was observed across all stages except first instars, indicating a density-dependent predation pattern constrained by handling time at higher prey densities. Adult females consistently emerged as the most potent predators, demonstrating the highest effectiveness of predation (1.591 on S. litura; 1.736 on S. frugiperda) and maximum predation rates (113.7 and 120.9 eggs, respectively). Adult males and fourth instar larvae also showed high predation capacities, with maximum consumption nearing 99 and 95 eggs. In contrast, first instars exhibited minimal predatory potential (effectiveness <0.017; maximum consumption <10 eggs), highlighting the critical role of developmental maturity in predation performance. Notably, predation on S. frugiperda eggs slightly surpassed that on S. litura, suggesting host-specific traits may modulate predator efficiency. The functional response curves confirmed a classic decelerating intake rate at high prey densities, characteristic of Type II predators. These findings affirm the high consumptive potential of H. axyridis, particularly adult females, as efficient natural enemies against Spodoptera spp. eggs, and provide actionable insights for their integration into targeted, stage-specific biological control programs.

Oenopia sauzeti (Mulsant) (Coccinellidae: Coleoptera) is a highly efficient predator of sap-sucking insect pests due to its high feeding capacity and broad prey range. The present investigation was carried out to find out the feeding potential and functional response of O. sauzeti fed on different densities of Macrosiphum euphorbiae (Thomas) (Aphididae: Hemiptera) nymphs in the in vitro condition with the overarching objective of appraising the ladybird beetle’s potential as a distinguished biological control agent. The newly emerged coccinellid grubs of a particular stage were reared individually on Petri plates with a known number of M. euphorbiae nymphs of a particular stage. The single individual of O. sauzeti consumed 1104.53, 936.53, 634.07, and 473.20 aphids in one generation when reared on the first, second, third, and fourth instars of M. euphorbiae, respectively. The female adult of predator recorded as a more voracious feeder compared to the male adult. O. sauzeti exhibits a type II functional response against potato aphid, and a significantly negative linear coefficient was obtained after logistic regression analysis for the proportion of prey consumed (Na/N) as a function of initial prey density (N). The functional response parameters, i.e. attack rate and handling time, were estimated by applying Roger’s random predator equation. The attack rate increased, and handling time decreased with the advancement of the development stage of the predator. The voracious nature of both adults and grubs of the ladybird beetle makes this effective biocontrol agent to be used in the Integrated Pest Management Programme against the potato aphid.

Eupeodes corollae (F.) (Diptera: Syrphidae) is the most abundant syrphid fly which is distributed worldwide and is the sole predator of aphids. Therefore, the present study was conducted to evaluate the predation rate and functional response of E. corollae against the cabbage aphid, Brevicoryne brassicae (L.). The experiment was carried out under laboratory conditions at 25 ± 2°C with 60–70% relative humidity. The results revealed that age-specific net predation rate (qx) increased after the 4th day and a peak was recorded on the 10th day of pivotal age in the third larval instar. The stable host kill rate and finite host kill rate of E. corollae were 18.63 and 21.07, respectively, against the B. brassicae and predicted that a mean of 20.78 aphids was needed for E. corollae to produce one offspring. A negative linear coefficient (P < 0) indicated the type II functional response for all larval instars of E. corollae against the B. brassicae. At higher prey density, the prey consumption was significantly at par with second and third instar larvae of E. corollae as the prey consumption was increased with increasing the prey density, which then decreased after attaining the upper asymptote (76.40 and 81.40% consumption, respectively). The Roger's predator random equation for type II functional response was fitted to estimate attack rate (a) and handling time (Th). The maximum prey consumption was recorded for third instar of E. corollae with a higher attack rate (0.336 h−1) and lower handling time (0.514 h) against B. brassicae, followed by the second and first instar. Thus, it is concluded that the third larval instar of E. corollae was the voracious feeder and used as an efficient biocontrol agent in the IPM programme.

The egg parasitoid Telenomus busseolae Gahan is the most important parasitoid of sugarcane pink borers and plays an important role in the suppression of their populations in Iran. To understand the efficiency of T. busseolae parasitizing Sesamia cretica Lederer, in this study, the functional response of the parasitoid was investigated at different temperatures (20, 25, 30 and 35 °C). The results of logistic regression indicated a type III functional response at all the temperatures. Roger's random parasite equation fitted the observed data at 30 and 35 °C, but Holling's disc equation fitted the data better at 20 and 25 °C. The attack rate of T. busseolae ranged from 0.0036 to 0.2148, 0.00017 to 0.1031, 0.0049 to 0.2952 and 0.0006 to 0.0382 per h, and the estimated handling time was 0.80, 0.48, 0.32 and 0.13 h at 20, 25, 30 and 35 °C, respectively.

We consider an infectious disease spreading along the edges of a network which may have significant clustering. The individuals in the population have heterogeneous infectiousness and/or susceptibility. We define the out-transmissibility of a node to be the marginal probability that it would infect a randomly chosen neighbor given its infectiousness and the distribution of susceptibility. For a given distribution of out-transmissibility, we find the conditions which give the upper (or lower) bounds on the size and probability of an epidemic, under weak assumptions on the transmission properties, but very general assumptions on the network. We find similar bounds for a given distribution of in-transmissibility (the marginal probability of being infected by a neighbor). We also find conditions giving global upper bounds on the size and probability. The distributions leading to these bounds are network independent. In the special case of networks with high girth (locally tree-like), we are able to prove stronger results. In general, the probability and size of epidemics are maximal when the population is homogeneous and minimal when the variance of in- or out-transmissibility is maximal.