Flower Mimics Roll Out Multicolored Carpets to Lure and Kill the House Fly

Abstract

Flowers and their spatial clustering are important parameters that mediate the foraging behavior and visitation rate of pollinating insects. Visual stimuli are crucial for triggering behavioral changes in the house fly, Musca domestica, which regularly visits plants for feeding and reproduction. The success of bait technology, which is the principal means of combatting flies, is adversely affected by reduced attractiveness and ineffective application techniques. Despite evidence that house flies have color vision capacity, respond to flowers, and exhibit color and pattern preference, the potential of artificial flowers as attractive factors has not been explored. The present study was performed to investigate whether artificial floral designs can lure and kill house flies. Starved wild house flies were presented with equal opportunities to acquire sugar meals, to which boric acid had been added as a toxin, from one flower arrangement (blue-dominated design, BDD; yellow-dominated design, YDD; or pink-dominated design, PDD), and a non-toxic white design (WDD). We also allowed house flies to forage within an enclosure containing two non-toxic floral designs (WDDs). The differences in mortality between the two environments with and without toxicant were examined. The survival rate of Musca domestica was extremely high when WDDs containing non-toxic sugar sources were the only feeding sites available. When given an option to forage in an environment containing a BDD and a WDD, house flies showed a high mortality rate (76%) compared to their counterparts maintained in the WDD environment (2%). When kept in an enclosure containing one YDD and a WDD, flies showed a mortality rate of 88%; however, no mortality occurred among flies confined to a compound with a WDD pair. When provided an even chance of foraging in an enclosure containing a mixed pair of floral arrangements (PDD and WDD) and another with two WDDs, flies showed a higher mortality rate (78%) in the first environment. However, the maximum survival rate (100%) was seen in the WDD environment. Exposure to YDD tended to result in a greater mortality rate than with the two other floral designs. Mortality gradually increased with time among flies exposed to tested artificial floral designs. The results presented here clearly indicated that artificial flower arrangements with a toxic sugar reward were strikingly attractive for house flies when their preferred color (white) was present. These observations offer novel possibilities for future development of flower mimic-based house fly control.

Keywords: boric acid; flower arrangement; housefly; mortality; sugar.

Figure 1

The experimental artificial floral designs used in this study. (1). Blue-dominated design (BDD). (2). Yellow-dominated design (YDD). (3). Pink-dominated design (PDD). (4). White-dominated design (WDD). (5). Nectar gland mimic present in all individual artificial flowers. BDD, YDD, and PDD were test floral designs, while WDD was the control. All these designs contained 15 artificial flowers arranged in a 3 × 5 design with the same amount of background greenery. All test floral designs possessed the same number of displayed colors but in varying proportions.

Figure 2

Bioassay layout. The two flower arrangements to be tested were placed at two opposite sides of the enclosure. To prevent position bias, we ran a dual-choice test design following a clockwise replication system, in which a test replicate corresponded to the disposition of two floral designs (one test design and one control design). The same replication strategy was also applied to control enclosures (two WDDs).

Figure 3

Mortality rates of the adult house flies when allowed to forage in an enclosure with a mixed pair of floral arrangements (one BDD delivering toxic sugar and one WDD with non-toxic sugar) and another enclosure with a pair of WDDs.

Figure 4

Mortality rates of the house flies when provided feeding opportunities in an enclosure with an assorted pair of floral arrangements (one YDD bearing toxic sugar and one WDD with non-toxic sugar) and another enclosure with paired WDDs.

Figure 5

Mortality rates of the house flies when they were placed in two different environments: one enclosure containing an assorted pair of floral designs (one PDD with toxic sugar and a WDD with non-toxic sugar) and a control enclosure containing two WDDs.