Brown Lacewings (Of Florida) (Insecta: Neuroptera: Hemerobiidae)1 Ellis G
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EENY225 Brown Lacewings (of Florida) (Insecta: Neuroptera: Hemerobiidae)1 Ellis G. MacLeod and Lionel A. Stange2 Introduction Micromus subanticus also is also found in the Keys and in the Caribbean. Hemerobius humulinus and H. stigma Brown lacewings are small to medium-sized insects (fore- are Holaretic, but the former is relatively uncommon in wing length 3 to 9 mm in Florida) that are predaceous both Florida. as adults and larvae. They prefer soft-bodied insects such as aphids, mealybugs, and also insect eggs. Because of the longevity of the adults, months in some species; voracious Biology appetites, for example Micromus posticus (Walker) larva Females lay non-stalked eggs, usually singly or in small consumed an average of 41 aphids during its life (Cutright groups. There are three larval instars. The 1st instar is active 1923); and high reproductive capacity, one female Hem- in all species. It can run fast, moving the head from side erobius humulinus Linnaeus can lay 460 eggs (Smith 1923); to side as it moves. In Sympherobius spp. and especially they are useful biological control agents. Some species have Boriomyia spp., the later instars are relatively immobile. A been used for this purpose, but limited work has been done. white cocoon of double structure (outer loose thread, inner In Texas, Sympherobius barberi Banks is mass reared for compact structure) is constructed in protected areas. Most control of the citrus mealybug (Hart, personal communica- groups appear to prefer aphids, but Sympherobius spp. may tion). Florida has a small fauna of 10 species in four genera, prefer coccid insects (especially mealybugs). Spiders are and this publication provides keys to identification of the considered one of the most important natural enemies of adults. There are 58 species in North American. lacewings. References on biology for species occurring in Florida are: Distribution • Cutright, 1923: Micromus posticus All the Florida species are found in northern Florida, and three of these, S. occidentalis, S. gracilis, and B. fidelis, were • Smith, 1923: Sympherobius amiculus, Hemerobius humuli- recorded for the first time for Florida from Gainesville. nus, H. stigma and M. posticus Boriomyia speciosa has not been rediscovered in Florida • Smith, 1934: S. barberi since Carpenter (1940) recorded it from Sanibel Island. Sympherobius amiculus, S. barberi, and H. stigma are known • MacLeod, 1960: Boriomyia fidelis as far south as Highlands County, whereas both species of Micromus are found throughout peninsula Florida. 1. This document is EENY-225 (originally published as DPI Entomology Circular 227), one of a series of Featured Creatures from the Entomology and Nematology Department, UF/IFAS Extension. Published: August 2001. Revised: June 2005. Reviewed July 2014. Visit the EDIS website at http://edis. ifas.ufl.edu. This document is also available on Featured Creatures website at http://entomology.ifas.ufl.edu/creatures. 2. Ellis G. MacLeod and Lionel A. Stange, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL. The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office. U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. Identification such as alfalfa. Brown lacewings resemble green lacewings (Chrysopidae) but are brownish and are less common. Adults have a wing venation with two or more branches There are 58 North American species. The eggs are laid on arising directly from the fused stem of R1 + Rs. The wing plants, but not stalked. The brown lacewing larvae differ membrane has microtrichia (contrasted with Chrysopidae), from green lacewing larvae in that they do not possess ovipositor not exerted, antenna moniliform, and front legs tubercles (a small knoblike or rounded protuberance). Both not raptorial. adults and larvae prey on aphids, other soft-bodied insects and mites. Figure 1. Adult brown lacewing (Neuroptera: Hemerobiidae). Credits: University of Florida Figure 3. Larva of a brown lacewing (Neuroptera: Hemerobiidae) preparing to attack and feed on an aphid. The black-colored aphid to the right was probably parasitized by a wasp. Credits: Lyle J. Buss, University of Florida Key to Genera and Species of Brown Lacewings of Florida (Wings and male terminalia after Carpenter 1940) 1. Forewing with costal area quite narrow at base, lacking a recurrent humeral vein (Figures 1, 2) . Micromus Figure 2. Adult brown lacewing Hemerobius sp. (Neuroptera: Rambur . 2 Hemerobiidae). Credits: Ken Gray, Oregon State University 1 ’. Costal area of forewing much broader basally (Figure 7), often abruptly broadened (Figures 4, 10) and always with a recurrent humeral vein . 3 Larvae have jaws that are fairly straight basally and curved apically, mandibles lacking teeth along medial margin, 2 (1). Inner gradate veins of forewing much more than their pretarsal claws lacking a trumpet-shaped empodium (a lengths apart (Figure 1); male terminalia as in Figure 3a . spine or lobelike process) (except 1st instar), and are not . Micromus subanticus (Walker) trash bearers, in contrast to many statements in older literature (e.g., Comstock 1925, Introduction to Entomology, • Observations: M. subanticus is found throughout Florida p. 297). and also in the Caribbean (Cuba, Dominican Republic, etc.). It occurs in a variety of habitats including both Detection and Survey trees and grasses. It is often found in alfalfa fields where Adults are commonly attracted to lights. Adults and larvae both larvae and adults feed on aphids. can be found by beating or sweeping plants, especially oaks and pines and plants with high aphid infestations Brown Lacewings (of Florida) (Insecta: Neuroptera: Hemerobiidae) 2 2’. Inner gradate crossveins of forewing at most only their origin of former (Figure 10) . Sympherobius Banks . lengths apart (Figure 2) ; male terminalia as in Figure 3b . 7 . Micromus posticus (Walker) 6 (5). Pronotum and mesonotum with broad yellow stripe; • Observations: In most of the Nearctic Region this is the upper process of male ectoproct forked distally (Figure 8) . most common Micromus, but in Florida it is apparently . Hemerobius humulinus Linnaeus somewhat less common than subanticus and does not occur in the Keys. Its habitats are similar to those of M. • Observations: This holarctic species appears to be un- subanticus. Smith (1923) and Cutright (1923) published common in Florida. Killington (1937) and Smith (1923) biological observations. provided biological data. 3 (1’). Forewing with three or more branches arising from 6’. Pronotum and mesonotum with, at most, a narrow the fused stem of R1 and Rs distal to separation of MA median stripe (this is often absent); mesonotum without (Figure 4); maxillary palpus 5-segmented, labial palpus defined stripe (Figure17); upper process of male ectoproct with three segments . Boriomyia Banks . 4 not forked (Figure 9) . .Hemerobius stigma Stephens 3’. Forewing with fewer than 3 branches arising from R1 + • Observations: This is the most common Hemerobius, Rs distal to separation of MA (Figure 7), most-basal branch ranging from the Panhandle to Highlands County. Smith arising from R1 + Rs often stalked with MA (Figure 10); (1923) gave some biological data. Adults hibernate. maxillary and labial palpi with a small peg-like apiculus so Tjeder (1960) synonymized stigmaterus Fitch. that they appear 6- and 4-segmented respectively (Figure 7 (5’). Forewing without radial crossvein; male ectoproct 16) . 5 with three processes, none bifurcate; upper process shorter than lower one (Figure11) . .Sympherobius barberi Banks 4 (3). Male paramere with lateral process not forked distally (Figure 6a); forewing usually lacking dark brown spots • Observations: This is the most widespread U.S. species around distal crossveins between branches of Cu (although and has been introduced into Hawaii for biological light-brown cloudings of the membrane adjacent to the control. It is being released in Texas or control of citrus crossveins may be present), usually with 2 broad transverse mealybug. In Florida there are records from Escambia light-brown bands paralleling the inner and outer series of County to Hillsborough County. gradate crossveins . Boriomyia fidelis (Banks) 7’. Forewing with radial crossvein (Figure 10, “rc”); male • Observations: Recorded here for the first time from ectoproct either with two processes, or, if three, one is Florida (34 specimens from Gainesville, March to bifurcate or the upper as long as lower one . 8 September). 8 (7’). Forewing vein Cul forks nearer hindmargin than to 4’. Male paramere with lateral process forked distally (Fig- crossvein m-cu; male ectoproct with two processes . ure 6b); forewing usually with discrete dark brown spots Sympherobius occidentalis Fitch around distal crossveins of Cu and the M-Cu crossvein, pale brown maculations sometimes present elsewhere, • Observations: This is an uncommon species