scholarly journals Post-Dropping Behavior of Potato Aphids (Macrosiphum euphorbiae)

2021 ◽  
Vol 34 (4) ◽  
pp. 223-239
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley

AbstractDropping behavior is an effective antipredator defense utilized by many insects including aphids, which drop from plants to lower plant parts or underlying substrates to avoid attack from predatory invertebrates. While research commonly focusses on triggers of dropping, less attention is given to what happens to prey individuals following escape drops. In this study, the duration of tonic immobility, recovery rates, and cases of “instant recovery” (re-clinging to lower plant parts) exhibited by potato aphids (Macrosiphum euphorbiae) that dropped from potted seedlings in response to introduced ladybird (Adalia bipunctata) adults, lacewing (Chrysoperla carnea) larvae, and a standardized tactile stimulus were investigated in relation to a range of environmental factors. Air temperature had a negative correlation with the duration of post-dropping tonic immobility; as temperature increased, time spent motionless decreased. Aphids also showed a pattern of increased recovery rate at higher temperatures. Aphids may be selected to move off the substrate quicker to avoid risks of overheating/desiccation at higher temperatures; and/or higher body temperature facilitates locomotion. Stimulus type also influenced recovery rate back to the original seedling, with aphids generally recovering after the standardized stimulus quicker than after dropping triggered by a real predator. Considering cases of instant recovery onto lower-reaches of the host seedling, seedling height influenced the likelihood of re-clinging, with aphids that managed to instantly recover dropping from, on average, taller seedlings than aphids that dropped to the substrate. Plant architecture could mitigate the costs of dropping for aphids, but further studies quantifying understory foliage cover are needed.

Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley

Abstract For herbivorous insects, dropping from the host plant is a commonly-observed antipredator defence. The use of dropping compared to other behaviours and its timing in relation to contact with a predator was explored in both pea aphids (Acyrthosiphon pisum) and potato aphids (Macrosiphum euphorbiae). Pea aphids dropped more frequently in response to ladybird adults (Adalia bipunctata) than lacewing larvae (Chrysoperla carnea). Potato aphids mainly walked away or backed-up in response to both predator types; but they dropped more frequently relative to other non-walking defences when faced with ladybird adults. Contact with a predator was an important influencer of dropping for both species, and most drops occurred from adjacent to the predator. Dropping appears to be a defence adaptively deployed only when the risk of imminent predation is high; factors that increase dropping likelihood include presence of faster-foraging predators such as adult ladybirds, predator proximity, and contact between aphid and predator.


1997 ◽  
Vol 129 (2) ◽  
pp. 241-249 ◽  
Author(s):  
G. Boiteau ◽  
W.P.L. Osborn

AbstractAdult potato aphids, Macrosiphum euphorbiae (Thomas), caged on potato terminal leaflets treated systemically with imidacloprid solutions ranging between 5.4 × 10−4 and 5.4 × 10−8 mL per mL water showed a significant reduction in the distance they travelled, time taken to travel a given distance, and flight propensity but no significant differences in the frequency or duration of short probing behaviour. The frequency of adult apterous potato aphids colonizing untreated potato leaflets or leaflets treated with an imidacloprid solution (5.4 × 10−4 mL per mL water) was not significantly different, indicating no repellency. Potato aphids moving from systemically treated to untreated leaflets did not recover much and their reduced walking ability was maintained for days. A 3-day exposure to vapour from an imidacloprid solution (5.4 × 10−4 mL per mL water) did not produce significant mortality or changes in nymphal production. The daily cumulative mortality obtained by caging potato aphids on potato leaflets placed in an imidacloprid solution (5.4 × 10−7 mL per mL water) was similar to that obtained in the field, on 20-day-old plants treated at planting with imidacloprid applied at 0.02 g Ai/m. None of the rates of imidacloprid tested stimulated the dispersal of apterous or alate potato aphids.


1997 ◽  
Vol 75 (9) ◽  
pp. 1396-1403 ◽  
Author(s):  
Gilles Boiteau

The relative ability of apterous and alate morphs of aphids to disperse from one potato leaflet to another was similar within species. Three species were tested: the buckthorn aphid, Aphis nasturtii Kaltenbach, the potato aphid, Macrosiphum euphorbiae (Thomas), and the green peach aphid, Myzus persicae (Sulzer). The average percentage of aphids moving daily from one leaflet to another never exceeded 2.5% for nymphs of the three species, but reached 45% for the adult winged buckthorn aphid. During the first half of the reproductive period, adult potato aphids were 1.5 times as likely as buckthorn aphids and twice as likely as green peach aphids to relocate daily. In a flight chamber, buckthorn aphids flew 4.5 times longer than green peach or potato aphids. The maiden flights of these summer forms were interrupted by repeated landings lasting less than 2 min. The maiden flights were interrupted more than twice as often for the buckthorn aphid as for the potato aphid. The number of flight interruptions was intermediate for the green peach aphid. Selected dispersal parameters for these aphid species are compared with those for the black bean aphid, Aphis fabae Scopoli, an occasional potato-colonizing species. The percentage of green peach and potato aphids taking flight was significantly correlated with the temperature in the flight chamber. The implication of these results for the distribution of aphid populations and the epidemiology of viral diseases is discussed.


2006 ◽  
Vol 19 (6) ◽  
pp. 655-664 ◽  
Author(s):  
Qi Li ◽  
Qi-Guang Xie ◽  
Jennifer Smith-Becker ◽  
Duroy A. Navarre ◽  
Isgouhi Kaloshian

The tomato Mi-1 gene confers resistance to root-knot nematodes (Meloidogyne spp.), potato aphids (Macrosiphum euphorbiae), and whiteflies (Bemisia tabaci and B. tabaci biotype B). Resistance to potato aphid is developmentally regulated and is not associated with induction of a hypersensitive response. The NahG transgene that eliminates endogenous salicylic acid (SA) was used to test the role of the SA signaling pathway in the resistance mediated by Mi-1 to potato aphids. Aphids survived longer on NahG tomato plants than on wild type. However, aphid reproduction was not affected on NahG tomato. Aphid resistance in Mi-1 NahG plants was completely abolished and the phenotype was successfully rescued by application of BTH (benzo(1,2,3)-thiaiazole-7-carbothioic acid S-methyl ester), indicating that the SA signaling pathway is an important component of Mi-1-mediated aphid resistance. Using virus-induced gene silencing, one or more mitogen-activated protein kinase (MAPK) cascades required for Mi-1-mediated aphid resistance were identified. Silencing plants for MAPK kinase (LeMKK2) and MAPKs (LeMPK2 and LeMPK1, or LeMPK3) resulted in attenuation of Mi-1-mediated aphid resistance. These results further demonstrate that resistance gene-mediated signaling events against piercing-sucking insects are similar to those against other plant pathogens.


1984 ◽  
Vol 116 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
Gregory P. Walker ◽  
Laurence V. Madden ◽  
Donald E. Simonet

AbstractSpatial dispersion of potato aphids was studied in fields of processing-tomatoes for 2 years to develop a sequential sampling scheme for the aphid. Potato aphids were found on upper, middle, and lower leaf strata in the percentages 60, 31, and 8. Dispersion was clumped, apterates more so than alates. Among-plant variance was generally greater than within-plant variance. There was a good linear relationship between mean crowding and the population mean and an excellent linear fit between log variance and log mean on all leaf strata for green and pink forms of the aphid and for alates and apterates. The log variance – log mean relationship was used as a basis for sequential sampling.


2015 ◽  
Vol 42 (1) ◽  
pp. 23-29 ◽  
Author(s):  
T.L. Grey ◽  
E.P. Prostko

ABSTRACT Laboratory and greenhouse studies were conducted to determine the absorption, translocation, dose response, efficacy, and effects on biomass of the herbicide diclosulam on bristly starbur (Acanthospermum hispidum DC.) In laboratory experiments, 14C-diclosulam absorption and translocation was evaluated in bristly starbur. Greenhouse studies determined bristly starbur growth response to postemergence applied diclosulam at 0, 0.2, 0.4, 0.8, 1.6, 3.3, and 6.5 g ai/ha. Bristly starbur seed were collected from two Georgia locations, hand cleaned, and grown in the greenhouse. Bristly starbur plants were then foliar treated with diclosulam when plants were in the 4 to 6 leaf stage of growth. 14C-diclosulam was applied to a single non-treated, most fully developed bristly starbur adaxial leaf, after the rest of the plant was foliar treated with 0.8 g ai/ha of diclosulam. At 24 and 48 hours after treatment, 14C-diclosulam was translocated acropetally in bristly starbur to the plant apex, with little to no movement to the lower plant parts including lower leaves, stem and roots. For the dose response studies, bristly starbur growth reduction dry weight (GR50) and efficacy (I50) for diclosulam ranged from 0.95 to 0.92 g ai/ha, respectively. Based on these data, bristly starbur susceptibility to diclosulam was due to its translocation to apical growing points within 24 to 48 hours where acetoacetate synthase (ALS) inhibition occurred resulting in eventual plant death. While bristly starbur is controlled with diclosulam rates below the standard use rate of other weeds, the standard field rates in combination with other herbicide mechanisms of action will continue to be recommended to peanut growers to reduce the potential for bristly starbur ALS resistance selection.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 760
Author(s):  
Oscar Giovanni Gutiérrez-Cárdenas ◽  
Ángeles Adán ◽  
Inés Beperet ◽  
Pilar Medina ◽  
Primitivo Caballero ◽  
...  

Baculoviruses (BV) are highly effective against lepidopteran pests of economic importance such as Spodoptera exigua. The combined use of entomopathogens and macrobiological control agents requires the study of their relationships. Laboratory bioassays were developed to evaluate the interactions between the multiple nucleopolyhedroviruses of S. exigua (SeMNPV) and Autographa californica (AcMNPV), and the predator Chrysoperla carnea. The microscopic examination of predator’s excreta (larval drops and meconia) after the ingestion of BV-infected S. exigua revealed the presence of viral occlusion bodies (OBs). The reinfection of S. exigua larvae with BVs-contaminated excreta by using OBs water suspensions or by direct application both yielded high mortality values but different speed-of-kill results. Meconia killed before in suspensions due to their higher viral load and larval excretion drops did so in direct application due to their liquid nature and their easiness of consumption. The prey-mediated ingestion of SeMNPV and AcMNPV triggered slight effects in C. carnea, which were probably derived from the food nutritional quality. Chrysoperla carnea larvae did not discriminate between healthy and BV-infected S. exigua, while a preference was shown for S. exigua (healthy or infected) vs. Macrosiphum euphorbiae. Our findings present C. carnea, and particularly its larvae, as a promissory candidate for BV dispersion in the field.


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