To determine if differences in life history parameters contribute to native species exclusion, immature development times, larval survivorship, reproductive life history parameters, and age-specific life tables were determined for two populations (eastern United States and western United States) of ninespotted lady beetles (Coccinella novemnotata Herbst) and one population of sevenspotted lady beetles (Coccinella septempunctata L.). Developing larvae were provided an ad libitum diet of pea aphids (Acyrthosiphon pisum Harris) at a constant temperature of 25°C. The first and fourth larval stadia of C. novemnotata were significantly longer than that of C. septempunctata, as was their total development time from egg to newly eclosed adult. Stage-specific developmental mortality was low for both species and did not exceed 7% for the entire development period. The preoviposition period of the two C. novemnotata populations was significantly shorter (15–20%) than that of C. septempunctata. C. novemnotata from both locations laid significantly fewer total eggs than C. septempunctata (34–40% fewer) over the 31-d test period, and also fewer eggs per day (37–43% fewer). The net reproductive rate of the C. novemnotata populations was 42–50% lower than that of C. septempunctata as was C. novemnotata's intrinsic rate of natural increase (rm: 0.1716 and 0.1840 vs. 0.1959 for western and eastern C. novemnotata and C. septempunctata, respectively).
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 43 • No. 4