Modeling Daphnia population dynamics and demography under natural conditions

Hydrobiologia ◽  
2003 ◽  
Vol 491 (1-3) ◽  
pp. 19-34 ◽  
Author(s):  
W.M. Mooij ◽  
S. Hülsmann ◽  
J. Vijverberg ◽  
A. Veen ◽  
E.H.R.R. Lammens
2017 ◽  
Vol 58 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Sanda Skejić ◽  
Slaven Jozić ◽  
Jacob Larsen ◽  
Olja Vidjak ◽  
Grozdan Kušpilić ◽  
...  

The unusual and prolonged occurrence of rare and poorly known dinoflagellate Prorocentrum arcuatum in the phytoplankton of the shallow aquaculture site in Medulin Bay was recorded from July 2013 to October 2014. This enabled us to investigate changes in abundance and environmental drivers of P. arcuatum population dynamics in natural conditions, and to provide first detailed description of P. arcuatum from field samples based on SEM images. During 15 months of observations we also recorded seasonal variability in P. arcuatum cell size. The optimum physical conditions for P. arcuatum proliferation were reached in autumn 2013, during the narrow temperature range between 19.6 oC – 20.4 oC, and salinity between 36.7 - 37.7. Despite the general similarity in physical conditions in autumn 2014, this increase in the abundance of P. arcuatum was not repeated, which might be connected to higher competition due to observed interannual changes in phytoplankton population structure.


2005 ◽  
Vol 62 (5) ◽  
pp. 473-477 ◽  
Author(s):  
Tironi Paulo ◽  
Adrian von Treuenfels ◽  
José Roberto Postali Parra

Cyrtomon luridus (Boheman) has adapted to the medicinal plant Duboisia sp., introduced from Australia. Its larvae feed on roots, causing up to 100% mortality damages. The population dynamics and biological cycle were studied to determine future control methods in Duboisia sp., in Arapongas, Paraná State, Brazil, from 1993 to 1996. C. luridus presented annual life cycle in Duboisia sp. under natural conditions. The larval development period was 120 to 150 days, from January to May, reaching an average size of 19.0 ± 2.0 mm in soil depth ranging on 24.9 ± 8.6 cm to 45.0 ± 10.0 cm. The beginning of the pupal phase happened in April. The larval-adult viability ranged on 7.5% to 19.6%. The typical symptoms of attack appeared in an infestation level of 60 larvae per plant. The first adults came out in July, six months after larvae hatching. However, adults came out from soil only in September, at the beginning of the rainy season, reaching the peak of emergency in October, outspreading until January. In laboratory (25ºC, 70% R.H.), females longevity averaged 113.7 ± 15.2 days. In this period, laying capacity was 42.7 ± 7.9 egg masses, with 9.4 ± 0.61 eggs each, totaling 402 ± 72.9 eggs per female. Adults C. luridus were found parasitized by Microctonus sp. (Loan) (Hymenoptera: Braconidae). Solanaceae species Solanum mauritianum Scopoli and Cestrum intermedium Sendt. were identified as host plants of C. luridus.


1995 ◽  
Vol 40 (7) ◽  
pp. 1215-1224 ◽  
Author(s):  
Maarten Boersma ◽  
Jacobus Vijverberg

2018 ◽  
Vol 23 (8) ◽  
pp. 1578 ◽  
Author(s):  
Elizeu Castro ◽  
Felipe Nuvoloni ◽  
Reinaldo Feres

Rubber trees, Hevea brasiliensis, are the main source of latex in the world, being cultivated in several states in Brazil. Calacarus heveae Feres and Tenuipalpus heveae Baker are considered the main pest mites of this crop. In this study, we evaluated the population dynamics of these two phytophagous species and of the most common predatory species during a one-year period on crops of rubber tree clones FDR 5788, CDC 312 and PMB 01, located in Igrapiúna, State of Bahia, northeastern Brazil. The results indicate that outbreaks of C. heveae and T. heveae occur from January to May. Population densities vary among clones, being lower on FDR 5788. Amblyseius perditus Chant and Baker (Phytoseiidae), Parapronematus sp. (Iolinidae) and Agistemus pallinii Matioli, Tavares and Pallini (Stigmaeidae) were the most abundant and frequently encountered predacious species. The population dynamics of these predatory species were related to the abundance of the phytophagous mites. However, the efficacy of these predators to mitigate infestations of phytophagous mites under natural conditions is unresolved due to the high reproductive rate of the phytophagous species.


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