Lestes congener

The two dark elongated spots on the latero-ventral thorax are diagnostic and give the species its common name. Distinguished from other Lestes species by this spotted pattern combined with the slaty gray thoracic coloration. The sexual dimorphism in eye color (blue males, brown females) is a useful field character. The 45-degree wing posture at rest separates it from pond damselflies (Coenagrionidae) that fold wings together above the body.

Found at the banks of permanent and temporary ponds, flooded river banks, slow-moving water, marshes, and swamps. On the Canadian prairies, specifically associated with pond habitats. Oviposition occurs in dry stems of emergent vegetation (Scirpus, Eleocharis obtusa) on dry land 0.5–3 m from the water's edge.

Widespread throughout North America, including Canada and the United States except the southeastern states. Documented from New York State, the Canadian prairies, and Vermont.

Adult flight period from late July to mid-September. Hatching is highly synchronous when temperatures exceed approximately 5°C. Adult emergence is synchronous. Sexual maturation requires approximately 3 weeks after emergence.

• Scirpus - oviposition substratedry stems used for egg-laying
• Eleocharis obtusa - oviposition substratedry stems on land 0.5–3 m from water's edge

Overwinters in the egg stage with a diapause just before blastokinesis; during diapause eggs are extremely resistant to low temperatures and desiccation. Post-diapause embryonic development can occur near 0°C but requires wetting as ponds fill in spring. Hatching is highly synchronous when temperature exceeds ~5°C. Larval development is rapid, completed in approximately 50 days. Adult emergence is synchronous. Sexual maturation requires 3 weeks.

Larvae exhibit consistent individual activity levels (behavioral syndrome) across different physiological states and predator cues, with activity reduced only in response to familiar predator cues. Larval behavioral type does not predict emergence behavior, indicating behavioral decoupling during ontogeny. Adults engage in tandem oviposition with contact guarding; pairs form away from water and fly to oviposition sites. Some copulations occur at or near oviposition sites with immediate oviposition afterward. Females may complete oviposition alone after mate desertion, most commonly in late afternoon when few lone males remain.

• Other Lestes speciesL. congener distinguished by the two dark elongated spots on the latero-ventral thorax; other spreadwings lack this specific spotted pattern or have different thoracic coloration.
• Coenagrionidae (pond damselflies)Lestidae hold wings at 45 degrees to body at rest; Coenagrionidae fold wings together above the abdomen.

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