Effects of White Mulberry (Morus alba) Heartwood Extract Against Reticulitermes flavipes (Blattodea: Rhinotermitidae).

Heartwood extract from white mulberry (Morus alba L.) (Rosales: Moraceae) were investigated for antitermitic activity against Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae) in laboratory experiments. An ethanol:toluene (2:1) solvent system was used to remove extract from heartwood shavings. A concentration-dependent feeding response and mortality were observed for termites exposed to a concentration series range of 1.25 to 10 mg/ml of extract based on their dry weight. Results showed that maximum termite mortality occurred at 10 mg/ml. Based on the concentration series data, LC50 was calculated at 1.71 mg/ml. In filter paper feeding and repellency assays, extract significantly decreased the total number of gut protozoa compared with untreated and solvent controls. After feeding on filter paper treated at 10 mg/ml for 2 wk, protozoan populations were reduced by >55%. In choice and no-choice tests with mulberry heartwood, greater wood loss from termite feeding was found on solvent extracted blocks compared with nonextracted. Complete (100%) mortality was observed after feeding on nonextracted blocks compared with extracted blocks. Heartwood extract from white mulberry imparted resistance to vacuum pressure treated, nondurable southern pine and cottonwood. At every concentration tested, 100% mortality was observed after feeding on extract-treated southern pine or cottonwood. GC-MS analysis of extract showed high levels of the phenol compound, resorcinol. Results indicated that heartwood extract from white mulberry have antitermitic properties and might be potentially valuable in the development of environmentally benign termiticides.

Laboratory Evaluations of Durability of Southern Pine Pressure Treated With Extractives From Durable Wood Species.

Extracts from sawdust of four naturally durable wood species [Alaskan yellow cedar, AYC, Cupressus nootkanansis D. Don 1824; eastern red cedar, ERC, Juniperus virginiana L.; honey mesquite, HM, Prosopis glandulosa Torr.; and black locust, BL, Robinia pseudoacacia L.] were used to treat southern pine, Pt, Pinus taeda L. sapwood blocks. Extractive treated blocks were evaluated for decay resistance in standard soil bottle fungal assays challenged with brown and white rot decay fungi. Results showed that extractives did impart some improvement to decay resistance of Pt blocks. BL- and HM-treated Pt blocks were also used in choice and no-choice assays to determine feeding preference and damage by eastern subterranean termites (Reticulitermes flavipes) Kollar. Minimal feeding on treated blocks was seen in both choice and no-choice assays. In choice assays, there was similar mortality between HM and BL arenas; however, in no-choice assays, complete mortality was recorded for HM-treated Pt and high mortality was seen with BL-treated Pt. Subsequent dose mortality termite assays showed HM to be effective in killing R. flavipes at low concentrations. Both HM and BL show promise as deterrents or termiticidal protectants and will be further evaluated in field studies.

Phenotypic Variation in Fitness Traits of a Managed Solitary Bee, Osmia ribifloris (Hymenoptera: Megachilidae).

We investigated fitness in natural populations of a managed solitary bee Osmia ribifloris Cockerell (Hymenoptera: Megachilidae) from sites separated from 400 to 2,700 km. Parental wild bees originated in central Texas (TX), central-northern Utah (UT), and central California (CA). They were then intercrossed and raised inside a mesh enclosure in southern Mississippi (MS). Females from all possible mated pairs of O. ribifloris produced F1 broods with 30-40% female cocoons and outcrossed progeny were 30% heavier. Mitochondrial (COI) genomes of the four populations revealed three distinct clades, a TX-CA clade, a UT clade, and an MS clade, the latter (MS) representing captive progeny of CA and UT bees. Although classified as separate subspecies, TX and CA populations from 30° N to 38° N latitude shared 98% similarity in COI genomes and the greatest brood biomass per nest straw (600- to 700-mg brood). Thus, TX and CA bees show greater adaptation for southern U.S. sites. In contrast, UT-sourced bees were more distantly related to TX and CA bees and also produced ∼50% fewer brood. These results, taken together, confirm that adult O. ribifloris from all trap-nest sites are genetically compatible, but some phenotypic variation exists that could affect this species performance as a commercial blueberry pollinator. Males, their sperm, or perhaps a substance in their sperm helped stabilize our captive bee population by promoting legitimate nesting over nest usurpation. Otherwise, without insemination, 50% fewer females nested (they nested 14 d late) and 20% usurped nests, killing 33-67% of brood in affected nests.