Assessment of the behaviour patterns of the lemon leaf-cutting ant, Atta sexdens rubropilosa (Hymenoptera: Formicidae), to natural sources of allelochemicals

1994 ◽  
Vol 84 (1) ◽  
pp. 91-95 ◽  
Author(s):  
Fernando J.M. Sales

AbstractReactions of the lemon leaf-cutting ant, Atta sexdens rubropilosa Forel, to natural sources of allelochemicals has been investigated at the University of Southampton. A linear hypothesis model in a randomized block design of a factorial experiment was utilized to assess the responses of the ants to the treatment combinations. When workers were offered flowers and leaves of the specified plant species simultaneously with mesocarp and endocarp of orange, they exhibited a consistent preference for the flowers. Flower fragments comprised 93.64% of the experimental material brought to the nest, leaves 6.20%, orange mesocarp 0.04% and orange endocarp 0.12%. Deterrent effects were noticed in leaves of Scilla spp. (Liliaceae) and the ants were chemically stimulated to explore, cut and transport the highly attractive flowers of Mahonia aquifolium (Berberidaceae).

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
EA Silva-Junior ◽  
CR Paludo ◽  
FS Nascimento ◽  
CR Currie ◽  
J Clardy ◽  
...  

Author(s):  
M. V. Dlamini ◽  
M. T. Masarirambi

Saline irrigation water is becoming an important water source as fresh water is fast becoming a scarce resource in many areas of the world, including Eswatini, especially in arid and semi-arid regions.  A study to test the response of two varieties of spinach (fordhook giant and mustard) to salinity was conducted in a field pot experiment at the Faculty of Agriculture at the Luyengo Campus of the University of Eswatini.  The treatments were laid in a randomized block design (RCBD).  The experiment consisted of four treatments, each replicated twelve times.  Treatments were salinity levels of 0.0 dS/m, 1.5 dS/m, 2.0 dS/m and 3.5 dS/m.  All the treatments were subjected to similar agronomic practices. Spinach was grown and observed for a period of five weeks.  Plant height was measured and the number of leaves counted weekly throughout the experiment. Significant differences (P < 0.05) between salinity treatments were obtained for plant height beginning in week 2 but were more pronounced in week 3, 4 and week 5.  No significant differences were obtained for the number of leaves.  There were however, clear significant differences between spinach irrigated with none saline irrigation water compared to saline irrigation water.   It was concluded that irrigating spinach with saline water of more than 2.0 dS/m drastically reduce plant growth but not the number of leaves under the conditions of the experiment.


2017 ◽  
Vol 23 (3) ◽  
pp. 357
Author(s):  
Daiane Da Silva Nóbrega ◽  
José Ricardo Peixoto ◽  
Michelle Souza Vilela ◽  
Fábio Gelape Faleiro ◽  
Karolline De Paula Silva Gomes ◽  
...  

Brazil has great variability, being one of the centers of origin of the genus Passiflora. Passion fruit has a multiple and diversified uses, being little explored as an ornamental plant in the country. The objective of this work was to characterize four passion fruit genotypes (two hybrid materials from the experimental field of passion fruit breeding program of the University of Brasília, and two passion fruit cultivars - BRS Sertão Forte and BRS Mel do Cerrado, both of them from Brazil), based on official and validated morphoagronomic descriptors for the identification of morphological aspects and ornamental potential, under field conditions, in the Distrito Federal, Brazil. The experiment consisted of a randomized block design, with four treatments, four replications, and six plants per plot. Plants were analyzed weekly regarding the characteristics of the branches, leaf blade, petiole, and flowers, with 24 measurements of each structure in the four treatments, which were recorded using a digital camera. Flowers presented pronounced size and color, colored branches, and leaves of varying sizes and shapes. All materials studied showed commercial ornamental potential to be explored as new options for ornamental climbing plants. 


2016 ◽  
Vol 8 (2) ◽  
pp. 176-180
Author(s):  
Abdul'Aziz AYINLA ◽  
Bolaji Umar OLAYINKA ◽  
Emmanuel Obukohwo ETEJERE

A field experiment was carried out to evaluate the influence of ground and unground rice straw application as organic manure on the yield and proximate composition of groundnut seeds, at the University of Ilorin teaching and research farm. The field layout was a split plot Complete Randomized Block Design with four replications. The ground and unground rice straw were in the main plot and different application rates of the rice straw (0; 1,250; 2,500; 3,750 and 5,000 kg /ha) were in the subplots. The results revealed that ground and unground rice straws at 1,250 and 2,500 kg/ha application rates significantly increased (p < 0.05) yield attributes such as pods’ number with a range of 48.33-74.33 pod weight (23.95-42.70), number of seeds (45.67-77.33), seeds’ weight (13.55-25.56 g) and hundred seed weight (34.34-38.05 g) as well as some aspect of proximate composition such as ash content, crude protein and crude fats which ranged between 2.71-2.79%, 31.47-31.56% and 46.61-47.13% respectively, in order of their mention. The forgoing study revealed that ground and unground rice straw applied at the rate of 1,250 and 2,500 kg/ha can serve as an alternative for soil nutrient amendment in groundnut as it ensured a reasonable yield that is able to meet the nutritional needs of man and livestock.


1996 ◽  
Vol 86 (3) ◽  
pp. 253-256 ◽  
Author(s):  
Maria José A. Hebling ◽  
Paulo Sérgio Maroti ◽  
Odair Correa Bueno ◽  
Osvaldo Aulino da Silva ◽  
Fernando Carlos Pagnocca

AbstractLaboratory nests of the leaf-cutting ant Atta sexdens rubropilosa Forel fed daily with leaves of Ricinus communis showed a gradual decrease in fungal garden volume, a higher ant mortality rate, and fungal garden extinction after 6 weeks. The mean oxygen consumption rate of these ants was higher than that of control ants collected from nests fed with leaves of Eucalyptus alba (Myrtaceae) suggesting one or more components of the leaves of R. communis had a direct physiological effect on the ants, in addition to inhibiting fungal garden growth.


2017 ◽  
Vol 74 (10) ◽  
pp. 1216-1225 ◽  
Author(s):  
Alexsandro S. Vieira ◽  
Manuela O. Ramalho ◽  
Cintia Martins ◽  
Vanderlei G. Martins ◽  
Odair C. Bueno

1990 ◽  
Vol 80 (3) ◽  
pp. 349-352 ◽  
Author(s):  
Fernando Carlos Pagnocca ◽  
Osvaldo Aulino da Silva ◽  
Maria Jose Hebling-Beraldo ◽  
Odair Correa Bueno ◽  
João Batista Fernandes ◽  
...  

AbstractExtracts of different sesame plant (Sesamum indicum) Linnaeus organs inhibited the in vitro growth of the fungus Leucocoprinus gongylophorus (Möller) (=Rozites gongylophora Möller), which is cultivated by the leaf-cutting ants of the species Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). The presence of the factor responsible for this inhibition was detected in methanol or chloroform extracts and is constant in the plant.


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