Impact of predatory carabids on below- and above-ground pests and yield in strawberry

Abstract

The impact of adult carabid beetles on below-and above-ground pests and fruit yield was examined in the laboratory and a two-year strawberry field study. In the laboratory, adults of Carabus nemoralis Muller, Nebria brevicollis (F.), Pterostichus algidus LeConte, Pterostichus melanarius (Illiger), and Scaphinotus marginatus Fischer (Coleoptera: Carabidae) consumed black vine weevil, Otiorhynchus sulcatus (F.) (Coleoptera: Curculionidae) eggs, larvae and/or pupae placed on the surface. The same five carabid species showed no impact or low removal rates of O. sulcatus larvae that had burrowed into the root of potted strawberry plants. In an assay with only P. melanarius, adults consumed O. sulcatus larvae placed on the soil surface more frequently than larvae buried 1.3 or 5 cm below. In a field study, the density of adult carabids, predominantly P. melanarius, was manipulated with augmented, exclusion, and open control plots (2 9 2 m). Manipulating carabid density had no impact on the removal of sentinel O. sulcatus larvae and pupae that were buried belowground which is consistent with laboratory observations. Increasing carabid density within augmented plots led to greater removal of red clover seeds, Trifolium pratense L., placed on the soil surface in the first year. Decreasing carabid density within exclusion plots resulted in fewer marketable fruits compared to control plots in both years. These results suggest that certain adult carabids may have limited impact belowground, and some beneficial impacts above-ground with pest control and crop protection.

A review of the sentinel prey method as a way of quantifying invertebrate predation under field conditions

“…A positive correlation was found between predation rate on real prey and the abundance of ground beetles (Speight & Lawton, ; Menalled et al ., ; Prasifka et al ., ), ground‐active predators in general (O'Neal et al ., ), or predatory insects (Chang & Snyder, ) but in some cases, this was not so (Pearce & Zalucki, ; Lee & Edwards, ).…”

“…Real prey was placed mostly above‐ground (median height = 1.1 m, range = 0.15–2.68 m, n = 33) in preference to ground level ( n = 17), with a single study (Lee & Edwards, ) using below‐ground prey. In 27 articles, the height from the ground was not specified.…”

“…Eggs were the most frequently used life stage (n = 52), followed by larvae (n = 14), pupae or nymphs (n = 11); only 3 studies (Brown & Mathews, 2008;Winqvist et al, 2011;Ximenez-Embun et al, 2014) used adults. Sentinels were mostly immobilised (n = 10) or naturally immobile (n = 62), but not always (n = 8), with 6 experiments (Mathews et al, 2004;Wiebe & Obrycki, 2004;Chen & Ruberson, 2008;Hong et al, 2011;Mathews et al, 2011;Lee & Edwards, 2012) using mobile and immobile prey simultaneously.…”

Biological Control beneath the Feet: A Review of Crop Protection against Insect Root Herbivores

“…Therefore, it is not surprising that biological control using generalist predators, which are influenced by the plethora of abiotic and biotic factors, may have been limited [118]. In this context, Lee and Edwards [65] showed that in laboratory conditions, five different carabidae species can consume various immature stages of the black vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae) occurring at the soil surface, although they were not efficient in controlling the root pest in the field; this is likely due to the burring behavior of pest larvae. Moreover, in some cases, arthropod predators even produced positive effects on target pests.…”

Endogaeic ground beetles fauna in oilseed rape field in Croatia

“…Besides hunting their prey aboveground, adult ground beetles frequently burrow beneath the soil and could potentially suppress pests belowground (Lee and Edwards, 2012;Schwerk and Dymitryszyn, 2015).…”