Measuring the Flight Ability of the Ambrosia Beetle, Platypus Quercivorus (Murayama), Using a Low-Cost, Small, and Easily Constructed Flight Mill

Summary

We developed a low cost and small flight mill, constructed with commonly available items and easily used in experimentation. Using this apparatus, we measured the flight ability of an ambrosia beetle, Platypus quercivorus.

Abstract

The ambrosia beetle, Platypus quercivorus (Murayama), is the vector of a fungal pathogen that causes mass mortality of Fagaceae trees (Japanese oak wilt). Therefore, knowing the dispersal capacity may help inform trapping/tree removal efforts to prevent this disease more effectively. In this study, we measured the flight velocity and duration and estimated the flight distance of the beetle using a newly developed flight mill. The flight mill is low cost, small, and constructed using commonly available items. Both the flight mill arm and its vertical axis comprise a thin needle. A beetle specimen is glued to one tip of the arm using instant glue. The other tip is thick due to being covered with plastic, thus it facilitates the detection of rotations of the arm. The revolution of the arm is detected by a photo sensor mounted on an infrared LED, and is indicated by a change in the output voltage when the arm passed above the LED. The photo sensor is connected to a personal computer and the output voltage data are stored at a sampling rate of 1 kHz. By conducting experiments using this flight mill, we found that P. quercivorus can fly at least 27 km. Because our flight mill comprises cheap and small ordinary items, many flight mills can be prepared and used simultaneously in a small laboratory space. This enables experimenters to obtain a sufficient amount of data within a short period.

Introduction

Animals migrate long distances in search of food and mates. Migrating animals might sometimes carry undesirable companions. The female ambrosia beetle, Platypus quercivorus (Murayama), is a known vector of the fungal pathogen, Raffaelea quercivora Kubono et Shin-Ito. This pathogen causes mass mortality of Fagaceae trees (Japanese oak wilt) and a high level of mortality¹. Since 1980, this disease has been expanding throughout Japan, and has become a serious problem².

P. quercivorus is a small insect (4-5 mm in body length and 4-6 mg in body weight), and yearl....

Protocol

1. Construction of a Flight Mill

1. Construction of a flight mill apparatus
   1. Cut off the plastic part from a needle (metal part: 40 mm in length and 0.25 mm in diameter; plastic part: 22 mm in length and 2 mm in diameter) with nippers (Figure 3).
   2. Fix this needle with an untreated needle in the shape of a cross with epoxy resin adhesive (Figure 3), referring them as a flight mill arm and an axial needle.
      NOTE: For an axial needle, the untreated side should be a bottom side. The uncovered tip of the flight mill arm is for gluing a beetle (

Results

In these experiments, about 50% of the beetles applied to the flight mill showed one or more revolutions. When the plastic part passed a virtual line between the sensor and the LED, the recorded voltage changed from about 0 V to about 6.5 V, and the duration of a passing was within 10-20 ms, depending on the flight velocity. Therefore, a spike-like voltage change is observed as one revolution (Figure 7B). We defined flight as when the flight mill arm revolved.......

Discussion

We developed a low-cost, easy-to-build, and compact flight mill for small insects such as P. quercivorus (4-5 mm in body length and 4-6 mg in body weight). Our flight mill comprised only ordinary items such as a needle, an IR LED, a photo sensor, instantaneous glue, etc., and did not require any sophisticated, expensive, or rare items such as computer-controlled electric devices. This enabled the easy and quick collection of necessary items and reduced experimental costs. Indeed, it cost only 1,000 JPY .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
needle	Seirin	J type No. 5 x 40 mm
epoxy resin adhesive	Konishi	#16113
metal plate			from a home improvement store
disposable plastic pipette			from a home improvement store
snap button			from a craft store
IR sensor	Hamamatsu Photonics	S7136
IR LED	OptoSupply	OSIR5113A	150 mW
custom-made program			downloadable from Github. URL: https://github.com/HidetoshiIkeno/FlightMill
instant glue	Toagosei	31204
A/D converter	LabJack Co.	U3-HV
DAQ software	AzeoTech	DAQFactoryExpress	download from AzeoTech Web page.