Bounds on Absolute Gypsy Moth (Lymantria dispar dispar) (Lepidoptera: Erebidae) Population Density as Derived from Counts in Single Milk Carton Traps

Abstract

Estimates of absolute pest population density are critical to pest management programs but have been difficult to obtain from capture numbers in pheromone-baited monitoring traps. In this paper, we establish a novel predictive relationship for a probability (spTfer(r)) of catching a male located at a distance r from the trap with a plume reach D.

How to count your bugs?

“…We tested this protocol for gypsy moth and estimated spTfer(0) = 0.15 and D50 = 45 ± 5 m. This spTfer(0) is lower than the actual experimental spTfer(0)=0.37 observed in the field (Onufrieva et al 2020).…”

“…We searched the literature for data on insect catches in traps located at various distances from the insect release points that satisfied the following conditions: (1) converged catch (meaning that the value did not increase substantially with increased trapping time, as defined in (Onufrieva et al, 2020) was reported for at least 4 distances between a trap and a release point, (2) number of insects released at large distance was the same or larger than at short distances, (3) no zero catch data points were reported between non-zero points. This search yielded 9 data sets on brown marmorated stink bug ( Halyomorpha halys ) (Kirkpatrick et al, 2019), codling moth ( Cydia pomonella ) (Adams et al, 2017), European pine sawfly ( Neodiprion sertifer ) (Östrand & Anderbrant, 2003), spotted wing drosophila ( Drosophila suzukii ) (Kirkpatrick et al, 2018), Western corn rootworm ( Diabrotica virgifera ) (Wamsley et al, 2006), Douglas fir beetle ( Dendroctonus pseudotsugae ) (Dodds & Ross, 2002), Southern pine beetle ( Dendroctonus frontalis ) (Turchin & Odendaal, 1996), macro-moths in families Erebidae (Merckx & Slade, 2014) and Sphingidae (Beck & Linsenmair, 2006).…”

“…We used the predictive relationship for a probability of catching an insect ( spT fer (r) ) located at a distance r from the trap that was developed for gypsy moth (Onufrieva et al 2020) to investigate if it could be applied to other insects.…”

“…For gypsy moth, a wealth of data points is available (Onufrieva et al, 2020), which allowed us to come up with the most robust protocol for fitting Equation 1 (see Results). Specifically, for gypsy moth, males were released at distances 0, 15, 25, 30, 45, 50, 60, 75, 80, 100, 150, 200, 250, 300, 500, 600, 900, 1000, 1200, and 1500 m from pheromone-baited traps, therefore, short and long distances were balanced and had equal weight in determination of D 50 .…”

“…In a recent study we analyzed a wealth of trap catch data collected for European gypsy moth Lymantria dispar dispar (L.) and derived a simple mathematical relationship between catch probability and distance to a pheromone-baited trap, which, in turn, allowed us to connect the actual trap catch with the most probably population density, along with statistical bounds on absolute gypsy moth population density (Onufrieva et al 2020). However, the key question remained unanswered: is there a general relationship of this type that might apply to all insects and trap types?…”